Excel to JSON Conversion

14 Oct 202424 minutes to read

Essential XlsIO supports to convert Excel data as JSON files by simply saving the workbook using the SaveAsJson method. This support includes the features:

• Save as a simple JSON file or a JSON file as schema
• Save a workbook to JSON
• Save a worksheet to JSON
• Save a range to JSON
• Save as a stream with the above features

Workbook to JSON as schema

The following code illustrates how to convert an Excel workbook to the JSON file or JSON file stream as schema.

C# [Cross-platform]

using (ExcelEngine excelEngine = new ExcelEngine())
{
	IApplication application = excelEngine.Excel;
	application.DefaultVersion = ExcelVersion.Xlsx;
	FileStream inputStream = new FileStream(Path.GetFullPath(@"Data/InputTemplate.xlsx"), FileMode.Open, FileAccess.Read);
	IWorkbook workbook = application.Workbooks.Open(inputStream);
	IWorksheet worksheet = workbook.Worksheets[0];

	#region save as JSON
	//Saves the workbook to a JSON filestream, as schema by default
	FileStream outputStream = new FileStream(Path.GetFullPath("Output/Excel-Workbook-To-JSON-as-schema-default.json"), FileMode.Create, FileAccess.ReadWrite);
	workbook.SaveAsJson(outputStream);

	//Saves the workbook to a JSON filestream as schema
	FileStream stream1 = new FileStream("Output/Excel-Workbook-To-JSON-as-schema.json", FileMode.Create, FileAccess.ReadWrite);
	workbook.SaveAsJson(stream1, true);
	#endregion

	//Dispose streams
	outputStream.Dispose();
	stream1.Dispose();
	inputStream.Dispose();

	#region Open JSON 
	//Open default JSON

	//Open JSON with Schema
	#endregion
}

C# [Windows-specific]

using(ExcelEngine excelEngine = new ExcelEngine())
{
  IApplication application = excelEngine.Excel;
  application.DefaultVersion = ExcelVersion.Xlsx;
  IWorkbook workbook = application.Workbooks.Open("Sample.xlsx", ExcelOpenType.Automatic);

  //Saves the workbook to a JSON file, as schema by default
  workbook.SaveAsJson("Excel-Workbook-To-JSON-as-schema-default.json");

  //Saves the workbook to a JSON file as schema
  workbook.SaveAsJson("Excel-Workbook-To-JSON-as-schema.json", true);

  //Saves the workbook to a JSON filestream, as schema by default
  FileStream stream = new FileStream("Excel-Workbook-To-JSON-filestream-as-schema-default.json", FileMode.Create);
  workbook.SaveAsJson(stream);

  //Saves the workbook to a JSON filestream as schema
  FileStream stream1 = new FileStream("Excel-Workbook-To-JSON-filestream-as-schema.json", FileMode.Create);
  workbook.SaveAsJson(stream1, true);
}

VB.NET [Windows-specific]

Using excelEngine As ExcelEngine = New ExcelEngine()
  Dim application As IApplication = excelEngine.Excel
  application.DefaultVersion = ExcelVersion.Xlsx
  Dim workbook As IWorkbook = application.Workbooks.Open("Sample.xlsx", ExcelOpenType.Automatic)

  'Saves the workbook to a JSON file, as schema by default
  workbook.SaveAsJson("Excel-Workbook-To-JSON-as-schema-default.json")
	
  'Saves the workbook to a JSON file as schema
  workbook.SaveAsJson("Excel-Workbook-To-JSON-as-schema.json", true)

  'Saves the workbook to a JSON filestream as schema by default
  Dim stream As FileStream = new FileStream("Excel-Workbook-To-JSON-filestream-as-schema-default.json", FileMode.Create)
  workbook.SaveAsJson(stream)

  'Saves the workbook to a JSON filestream as schema
  Dim stream1 As FileStream = new FileStream("Excel-Workbook-To-JSON-filestream-as-schema.json",FileMode.Create)
  workbook.SaveAsJson(stream1, true)
End Using

UWP

using (ExcelEngine excelEngine = new ExcelEngine())
{
  //Gets assembly
  Assembly assembly = typeof(App).GetTypeInfo().Assembly;

  //Gets input Excel document from embedded resource collection
  Stream inputStream = assembly.GetManifestResourceStream("Sample.xlsx");
  IWorkbook workbook = await excelEngine.Excel.Workbooks.OpenAsync(inputStream);
  IWorksheet worksheet = workbook.Worksheets[0];

  //Initializes FileSavePicker
  FileSavePicker savePicker = new FileSavePicker();
  savePicker.SuggestedStartLocation = PickerLocationId.Desktop;
  savePicker.SuggestedFileName = "Excel-To-JSON-as-schema-default";
  savePicker.FileTypeChoices.Add("JSON Files", new List<string>() { ".json" });

  //Creates a storage file from FileSavePicker
  StorageFile storageFile = await savePicker.PickSaveFileAsync();

  //Saves the workbook to a JSON as specified storage file, as schema by default
  await workbook.SaveAsJsonAsync(storageFile);

  //Saves the workbook to a JSON filestream, as schema by default
  MemoryStream stream = new MemoryStream();
  workbook.Version = ExcelVersion.Xlsx;
  await workbook.SaveAsJsonAsync(stream);
  Save(stream, "Excel-Workbook-To-JSON-filestream-as-schema-default.json");

  stream.Dispose();
  inputStream.Dispose();
}

//Save the workbook stream as a file.

#region Setting output location
async void Save(Stream stream, string filename)
{
  stream.Position = 0;

  StorageFile stFile;
  if (!(Windows.Foundation.Metadata.ApiInformation.IsTypePresent("Windows.Phone.UI.Input.HardwareButtons")))
  {
    FileSavePicker savePicker = new FileSavePicker();
    savePicker.DefaultFileExtension = ".json";
    savePicker.SuggestedFileName = filename;
    savePicker.FileTypeChoices.Add("JSON Files", new List<string>() { ".json" });
    stFile = await savePicker.PickSaveFileAsync();
  }
  else
  {
    StorageFolder local = Windows.Storage.ApplicationData.Current.LocalFolder;
    stFile = await local.CreateFileAsync(filename, CreationCollisionOption.ReplaceExisting);
  }
  if (stFile != null)
  {
    Windows.Storage.Streams.IRandomAccessStream fileStream = await stFile.OpenAsync(FileAccessMode.ReadWrite);
    Stream st = fileStream.AsStreamForWrite();
    st.Write((stream as MemoryStream).ToArray(), 0, (int)stream.Length);
    st.Flush();
    st.Dispose();
    fileStream.Dispose();
  }
}
#endregion

A complete working example to convert Excel to JSON with schema in C# is present on this GitHub page.

Workbook to JSON without schema

The following code illustrates how to convert an Excel workbook to the JSON file or JSON file stream without schema.

C# [Cross-platform]

using (ExcelEngine excelEngine = new ExcelEngine())
{
	IApplication application = excelEngine.Excel;
	application.DefaultVersion = ExcelVersion.Xlsx;
	FileStream inputStream = new FileStream(Path.GetFullPath(@"Data/InputTemplate.xlsx"), FileMode.Open, FileAccess.Read);
	IWorkbook workbook = application.Workbooks.Open(inputStream);
	IWorksheet worksheet = workbook.Worksheets[0];

	#region save as JSON
	//Saves the workbook to a JSON file without schema
	FileStream outputStream = new FileStream("Output/Workbook-To-JSON-without-schema.json", FileMode.Create);
	workbook.SaveAsJson(outputStream,false);
	#endregion

	//Dispose streams
	outputStream.Dispose();
	inputStream.Dispose();

	#region Open JSON 
	//Open default JSON
	#endregion
}

C# [Windows-specific]

using(ExcelEngine excelEngine = new ExcelEngine())
{
  IApplication application = excelEngine.Excel;
  application.DefaultVersion = ExcelVersion.Xlsx;
  IWorkbook workbook = application.Workbooks.Open("Sample.xlsx", ExcelOpenType.Automatic);

  //Saves the workbook to a JSON file without schema
  workbook.SaveAsJson("Excel-Workbook-To-JSON-without-schema.json", false);

  //Saves the workbook to a JSON filestream without schema
  FileStream stream = new FileStream("Excel-Workbook-To-JSON-filestream-without-schema.json", FileMode.Create);
  workbook.SaveAsJson(stream, false);
}

VB.NET [Windows-specific]

Using excelEngine As ExcelEngine = New ExcelEngine()
  Dim application As IApplication = excelEngine.Excel
  application.DefaultVersion = ExcelVersion.Xlsx
  Dim workbook As IWorkbook = application.Workbooks.Open("Sample.xlsx", ExcelOpenType.Automatic)

  'Saves the workbook to a JSON file without schema
  workbook.SaveAsJson("Excel-Workbook-To-JSON-without-schema.json", false)

  'Saves the workbook to a JSON filestream without schema
  Dim stream As FileStream = new FileStream("Excel-Workbook-To-JSON-filestream-without-schema.json", FileMode.Create)
  workbook.SaveAsJson(stream, false)
End Using

UWP

using (ExcelEngine excelEngine = new ExcelEngine())
{
  //Gets assembly
  Assembly assembly = typeof(App).GetTypeInfo().Assembly;

  //Gets input Excel document from embedded resource collection
  Stream inputStream = assembly.GetManifestResourceStream("Sample.xlsx");
  IWorkbook workbook = await excelEngine.Excel.Workbooks.OpenAsync(inputStream);
  IWorksheet worksheet = workbook.Worksheets[0];

  //Initializes FileSavePicker
  FileSavePicker savePicker = new FileSavePicker();
  savePicker.SuggestedStartLocation = PickerLocationId.Desktop;
  savePicker.SuggestedFileName = "Excel-To-JSON-without-schema";
  savePicker.FileTypeChoices.Add("JSON Files", new List<string>() { ".json" });

  //Creates a storage file from FileSavePicker
  StorageFile storageFile = await savePicker.PickSaveFileAsync();

  //Saves workbook to JSON as specified storage file without schema
  await workbook.SaveAsJsonAsync(storageFile, file);

  //Saves the workbook to a JSON filestream without schema
  MemoryStream stream = new MemoryStream();
  workbook.Version = ExcelVersion.Xlsx;
  await workbook.SaveAsJsonAsync(stream, false);
  Save(stream, "Excel-Workbook-To-JSON-filestream-without-schema.json");

  stream.Dispose();
}

//Save the worksheet stream as a file.

#region Setting output location
async void Save(Stream stream, string filename)
{
  stream.Position = 0;

  StorageFile stFile;
  if (!(Windows.Foundation.Metadata.ApiInformation.IsTypePresent("Windows.Phone.UI.Input.HardwareButtons")))
  {
    FileSavePicker savePicker = new FileSavePicker();
    savePicker.DefaultFileExtension = ".json";
    savePicker.SuggestedFileName = filename;
    savePicker.FileTypeChoices.Add("JSON Files", new List<string>() { ".json" });
    stFile = await savePicker.PickSaveFileAsync();
  }
  else
  {
    StorageFolder local = Windows.Storage.ApplicationData.Current.LocalFolder;
    stFile = await local.CreateFileAsync(filename, CreationCollisionOption.ReplaceExisting);
  }
  if (stFile != null)
  {
    Windows.Storage.Streams.IRandomAccessStream fileStream = await stFile.OpenAsync(FileAccessMode.ReadWrite);
    Stream st = fileStream.AsStreamForWrite();
    st.Write((stream as MemoryStream).ToArray(), 0, (int)stream.Length);
    st.Flush();
    st.Dispose();
    fileStream.Dispose();
  }
}
#endregion

A complete working example to convert Excel to JSON without schema in C# is present on this GitHub page.

Worksheet to JSON as schema

The following code illustrates how to convert an Excel worksheet to the JSON file or JSON file stream with schema.

C# [Cross-platform]

using (ExcelEngine excelEngine = new ExcelEngine())
{
	IApplication application = excelEngine.Excel;
	application.DefaultVersion = ExcelVersion.Xlsx;
	FileStream inputStream = new FileStream(Path.GetFullPath(@"Data/InputTemplate.xlsx"), FileMode.Open, FileAccess.Read);
	IWorkbook workbook = application.Workbooks.Open(inputStream);
	IWorksheet worksheet = workbook.Worksheets[0];

	#region save as JSON
	//Saves the workbook to a JSON filestream, as schema by default
	FileStream outputStream = new FileStream("Output/Excel-Worksheet-To-JSON-filestream-as-schema-default.json", FileMode.Create);
	workbook.SaveAsJson(outputStream, worksheet);

	//Saves the workbook to a JSON filestream as schema
	FileStream stream1 = new FileStream("Output/Excel-Worksheet-To-JSON-filestream-as-schema.json", FileMode.Create, FileAccess.ReadWrite);
	workbook.SaveAsJson(stream1, worksheet, true);
	#endregion

	//Dispose streams
	outputStream.Dispose();
	stream1.Dispose();
	inputStream.Dispose();

	#region Open JSON 
	//Open default JSON

	//Open JSON with Schema
	#endregion
}

C# [Windows-specific]

using(ExcelEngine excelEngine = new ExcelEngine())
{
  IApplication application = excelEngine.Excel;
  application.DefaultVersion = ExcelVersion.Xlsx;
  IWorkbook workbook = application.Workbooks.Open("Sample.xlsx", ExcelOpenType.Automatic);

  //Active worksheet
  IWorksheet worksheet = workbook.Worksheets[0];

  //Saves the worksheet to a JSON file, as schema by default
  workbook.SaveAsJson("Excel-Worksheet-To-JSON-as-schema-default.json", worksheet);

  //Saves the worksheet to a JSON file as schema
  workbook.SaveAsJson("Excel-Worksheet-To-JSON-as-schema.json", worksheet, true);

  //Saves the worksheet to a JSON filestream, as schema by default
  FileStream stream = new FileStream("Excel-Worksheet-To-JSON-filestream-as-schema-default.json", FileMode.Create);
  workbook.SaveAsJson("stream", worksheet);

  //Saves the worksheet to a JSON filestream as schema
  FileStream stream1 = new FileStream("Excel-Worksheet-To-JSON-filestream-as-schema.json", FileMode.Create);
  workbook.SaveAsJson(stream1, worksheet, true);
}

VB.NET [Windows-specific]

Using excelEngine As ExcelEngine = New ExcelEngine()
  Dim application As IApplication = excelEngine.Excel
  application.DefaultVersion = ExcelVersion.Xlsx
  Dim workbook As IWorkbook = application.Workbooks.Open("Sample.xlsx", ExcelOpenType.Automatic)

  'Active worksheet
  Dim worksheet As IWorksheet = workbook.Worksheets(0)

  'Saves the worksheet to a JSON file, as schema by default
  workbook.SaveAsJson("Excel-Worksheet-To-JSON-as-schema-default.json", worksheet)

  'Saves the worksheet to a JSON file as schema
  workbook.SaveAsJson("Excel-Worksheet-To-JSON-as-schema.json", worksheet, true)

  'Saves the worksheet to a JSON filestream as schema by default
  Dim stream As FileStream = new FileStream("Excel-Worksheet-To-JSON-filestream-as-schema-default.json",FileMode.Create)
  workbook.SaveAsJson(stream, worksheet)

  'Saves the worksheet to a JSON filestream as schema
  Dim stream1 As FileStream = new FileStream("Excel-Worksheet-To-JSON-filestream-as-schema.json",FileMode.Create)
  workbook.SaveAsJson(stream1, worksheet, true)
End Using

UWP

using (ExcelEngine excelEngine = new ExcelEngine())
{
  //Gets assembly
  Assembly assembly = typeof(App).GetTypeInfo().Assembly;

  //Gets input Excel document from embedded resource collection
  Stream inputStream = assembly.GetManifestResourceStream("Sample.xlsx");
  IWorkbook workbook = await excelEngine.Excel.Workbooks.OpenAsync(inputStream);
  IWorksheet worksheet = workbook.Worksheets[0];

  //Initializes FileSavePicker
  FileSavePicker savePicker = new FileSavePicker();
  savePicker.SuggestedStartLocation = PickerLocationId.Desktop;
  savePicker.SuggestedFileName = "Excel-To-JSON-filestream-as-schema-default";
  savePicker.FileTypeChoices.Add("JSON Files", new List<string>() { ".json" });

  //Creates a storage file from FileSavePicker
  StorageFile storageFile = await savePicker.PickSaveFileAsync();

  //Saves the worksheet to JSON as specified storage file, as schema by default
  await workbook.SaveAsJsonAsync(storageFile, worksheet);

  //Saves the worksheet to a JSON filestream, as schema by default
  MemoryStream stream = new MemoryStream();
  workbook.Version = ExcelVersion.Xlsx;
  await workbook.SaveAsJsonAsync(stream, worksheet);
  Save(stream, "Excel-Worksheet-To-JSON-filestream-as-schema-default.json");
}

//Save the worksheet stream as a file.

#region Setting output location
async void Save(Stream stream, string filename)
{
  stream.Position = 0;

  StorageFile stFile;
  if (!(Windows.Foundation.Metadata.ApiInformation.IsTypePresent("Windows.Phone.UI.Input.HardwareButtons")))
  {
    FileSavePicker savePicker = new FileSavePicker();
    savePicker.DefaultFileExtension = ".json";
    savePicker.SuggestedFileName = filename;
    savePicker.FileTypeChoices.Add("JSON Files", new List<string>() { ".json" });
    stFile = await savePicker.PickSaveFileAsync();
  }
  else
  {
    StorageFolder local = Windows.Storage.ApplicationData.Current.LocalFolder;
    stFile = await local.CreateFileAsync(filename, CreationCollisionOption.ReplaceExisting);
  }
  if (stFile != null)
  {
    Windows.Storage.Streams.IRandomAccessStream fileStream = await stFile.OpenAsync(FileAccessMode.ReadWrite);
    Stream st = fileStream.AsStreamForWrite();
    st.Write((stream as MemoryStream).ToArray(), 0, (int)stream.Length);
    st.Flush();
    st.Dispose();
    fileStream.Dispose();
  }
}
#endregion

A complete working example to convert Excel worksheet to JSON with schema in C# is present on this GitHub page.

Worksheet to JSON without schema

The following code illustrates how to convert an Excel worksheet to the JSON file or file stream without schema.

C# [Cross-platform]

using (ExcelEngine excelEngine = new ExcelEngine())
{
	IApplication application = excelEngine.Excel;
	application.DefaultVersion = ExcelVersion.Xlsx;
	FileStream inputStream = new FileStream(Path.GetFullPath(@"Data/InputTemplate.xlsx"), FileMode.Open, FileAccess.Read);
	IWorkbook workbook = application.Workbooks.Open(inputStream);
	IWorksheet worksheet = workbook.Worksheets[0];

	#region save as JSON
	//Saves the workbook to a JSON filestream, as schema by default
	FileStream outputStream = new FileStream(Path.GetFullPath("Output/Excel-Worksheet-To-JSON-filestream-without-schema.json"), FileMode.Create, FileAccess.ReadWrite);
	workbook.SaveAsJson(outputStream, worksheet,false);
	#endregion

	//Dispose streams
	outputStream.Dispose();
	inputStream.Dispose();

	#region Open JSON 
	//Open default JSON
	#endregion
}

C# [Windows-specific]

using(ExcelEngine excelEngine = new ExcelEngine())
{
  IApplication application = excelEngine.Excel;
  application.DefaultVersion = ExcelVersion.Xlsx;
  IWorkbook workbook = application.Workbooks.Open("Sample.xlsx", ExcelOpenType.Automatic);

  //Active worksheet
  IWorksheet worksheet = workbook.Worksheets[0];

  //Saves the worksheet to a JSON file without schema
  workbook.SaveAsJson("Excel-Worksheet-To-JSON-without-schema.json", worksheet, false);

  //Saves the worksheet to a JSON filestream without schema
  FileStream stream = new FileStream("Excel-Worksheet-To-JSON-filestream-without-schema.json", FileMode.Create); 
  workbook.SaveAsJson(stream, worksheet, false);
}

VB.NET [Windows-specific]

Using excelEngine As ExcelEngine = New ExcelEngine()
  Dim application As IApplication = excelEngine.Excel
  application.DefaultVersion = ExcelVersion.Xlsx
  Dim workbook As IWorkbook = application.Workbooks.Open("Sample.xlsx", ExcelOpenType.Automatic)

  'Active worksheet
  Dim worksheet As IWorksheet = workbook.Worksheets(0)

  'Saves the worksheet to a JSON file without schema
  workbook.SaveAsJson("Excel-Worksheet-To-JSON-without-schema.json", worksheet, false)

  'Saves the worksheet to a JSON filestream without schema
  Dim stream As FileStream = new FileStream("Excel-Worksheet-To-JSON-filestream-without-schema.json", FileMode.Create)
  workbook.SaveAsJson(stream, worksheet, false)
End Using

UWP

using (ExcelEngine excelEngine = new ExcelEngine())
{
  //Gets assembly
  Assembly assembly = typeof(App).GetTypeInfo().Assembly;

  //Gets input Excel document from embedded resource collection
  Stream inputStream = assembly.GetManifestResourceStream("Sample.xlsx");
  IWorkbook workbook = await excelEngine.Excel.Workbooks.OpenAsync(inputStream);
  IWorksheet worksheet = workbook.Worksheets[0];

  //Initializes FileSavePicker
  FileSavePicker savePicker = new FileSavePicker();
  savePicker.SuggestedStartLocation = PickerLocationId.Desktop;
  savePicker.SuggestedFileName = "Excel-To-JSON";
  savePicker.FileTypeChoices.Add("JSON Files", new List<string>() { ".json" });

  //Creates a storage file from FileSavePicker
  StorageFile storageFile = await savePicker.PickSaveFileAsync();

  //Saves the to worsheet to a JSON as specified storage file without schema
  await workbook.SaveAsJsonAsync(storageFile, worksheet, false);

  //Saves the worsheet to a JSON filestream without schema
  MemoryStream stream = new MemoryStream();
  workbook.Version = ExcelVersion.Xlsx;
  await workbook.SaveAsJsonAsync(stream, worksheet, false);
  Save(stream, "Excel-Worksheet-To-JSON-filestream-without-schema.json");

  stream.Dispose();
}

//Save the worksheet stream as a file.

#region Setting output location
async void Save(Stream stream, string filename)
{
  stream.Position = 0;

  StorageFile stFile;
  if (!(Windows.Foundation.Metadata.ApiInformation.IsTypePresent("Windows.Phone.UI.Input.HardwareButtons")))
  {
    FileSavePicker savePicker = new FileSavePicker();
    savePicker.DefaultFileExtension = ".json";
    savePicker.SuggestedFileName = filename;
    savePicker.FileTypeChoices.Add("JSON Files", new List<string>() { ".json" });
    stFile = await savePicker.PickSaveFileAsync();
  }
  else
  {
    StorageFolder local = Windows.Storage.ApplicationData.Current.LocalFolder;
    stFile = await local.CreateFileAsync(filename, CreationCollisionOption.ReplaceExisting);
  }
  if (stFile != null)
  {
    Windows.Storage.Streams.IRandomAccessStream fileStream = await stFile.OpenAsync(FileAccessMode.ReadWrite);
    Stream st = fileStream.AsStreamForWrite();
    st.Write((stream as MemoryStream).ToArray(), 0, (int)stream.Length);
    st.Flush();
    st.Dispose();
    fileStream.Dispose();
  }
}
#endregion

A complete working example to convert Excel worksheet to JSON without schema in C# is present on this GitHub page.

Range to JSON as schema

The following code illustrates how to convert an Excel Custom Range to the JSON file or file stream as schema.

C# [Cross-platform]

using (ExcelEngine excelEngine = new ExcelEngine())
{
	IApplication application = excelEngine.Excel;
	application.DefaultVersion = ExcelVersion.Xlsx;
	FileStream inputStream = new FileStream(Path.GetFullPath(@"Data/InputTemplate.xlsx"), FileMode.Open, FileAccess.Read);
	IWorkbook workbook = application.Workbooks.Open(inputStream);
	IWorksheet worksheet = workbook.Worksheets[0];

	//Custom range
	IRange range = worksheet.Range["A1:F100"];

	#region save as JSON
	//Saves the workbook to a JSON filestream, as schema by default
	FileStream outputStream = new FileStream(Path.GetFullPath("Output/Excel-Range-To-JSON-as-schema-default.json"), FileMode.Create, FileAccess.ReadWrite);
	workbook.SaveAsJson(outputStream, range);

	//Saves the workbook to a JSON filestream as schema
	FileStream stream1 = new FileStream("Output/Excel-Range-To-JSON-as-schema.json", FileMode.Create, FileAccess.ReadWrite);
	workbook.SaveAsJson(stream1, range, true);
	#endregion

	//Dispose streams
	outputStream.Dispose();
	stream1.Dispose();
	inputStream.Dispose();

	#region Open JSON 
	//Open default JSON

	//Open JSON with Schema
	#endregion
}

C# [Windows-specific]

using(ExcelEngine excelEngine = new ExcelEngine())
{
  IApplication application = excelEngine.Excel;
  application.DefaultVersion = ExcelVersion.Xlsx;
  IWorkbook workbook = application.Workbooks.Open("Sample.xlsx", ExcelOpenType.Automatic);

  //Active worksheet
  IWorksheet worksheet = workbook.Worksheets[0];

  //Custom range
  IRange range = worksheet.Range["A2:A5"];

  //Saves the range to a JSON file, as schema by default
  workbook.SaveAsJson("Excel-Range-To-JSON-as-schema-default.json", range);

  //Saves the range to a JSON file as schema
  workbook.SaveAsJson("Excel-Range-To-JSON-as-schema.json", range, true);

  //Saves the range to a JSON filestream, as schema by default
  FileStream stream = new FileStream("Excel-Range-To-JSON-filestream-as-schema-default.json", FileMode.Create);
  workbook.SaveAsJson(stream, range);

  //Saves the range to a JSON filestream as schema
  FileStream stream1 = new FileStream("Excel-Range-To-JSON-filestream-as-schema.json", FileMode.Create);
  workbook.SaveAsJson(stream1, range, true);
}

VB.NET [Windows-specific]

Using excelEngine As ExcelEngine = New ExcelEngine()
  Dim application As IApplication = excelEngine.Excel
  application.DefaultVersion = ExcelVersion.Xlsx
  Dim workbook As IWorkbook = application.Workbooks.Open("Sample.xlsx", ExcelOpenType.Automatic)

  'Active worksheet
  Dim worksheet As IWorksheet = workbook.Worksheets(0)

  'Custom range
  Dim range As IRange = worksheet.Range("A2:A5")

  'Saves the range to a JSON file, as schema by default
  workbook.SaveAsJson("Excel-Range-To-JSON-as-schema-default.json", range)

  'Saves the range to a JSON file as schema
  workbook.SaveAsJson("Excel-Range-To-JSON-as-schema.json", range, true)

  'Saves the range to a JSON filestream, as schema by default
  Dim stream As FileStream = new FileStream("Excel-Range-To-JSON-filestream-as-schema-default.json", FileMode.Create)
  workbook.SaveAsJson(stream, range)

  'Saves the range to a JSON filestream as schema
  Dim stream1 As FileStream = new FileStream("Excel-Range-To-JSON-filestream-as-schema.json", FileMode.Create)
  workbook.SaveAsJson(stream1, range, true)
End Using

UWP

using (ExcelEngine excelEngine = new ExcelEngine())
{
  //Gets assembly
  Assembly assembly = typeof(App).GetTypeInfo().Assembly;

  //Gets input Excel document from embedded resource collection
  Stream inputStream = assembly.GetManifestResourceStream("Sample.xlsx");
  IWorkbook workbook = await excelEngine.Excel.Workbooks.OpenAsync(inputStream);
  IWorksheet worksheet = workbook.Worksheets[0];

  //Custom range
  IRange range = worksheet.Range["A2:A5"];

  //Initializes FileSavePicker
  FileSavePicker savePicker = new FileSavePicker();
  savePicker.SuggestedStartLocation = PickerLocationId.Desktop;
  savePicker.SuggestedFileName = "Excel-To-JSON-as-schema-default";
  savePicker.FileTypeChoices.Add("JSON Files", new List<string>() { ".json" });

  //Creates a storage file from FileSavePicker
  StorageFile storageFile = await savePicker.PickSaveFileAsync();

  //Saves the Range to a JSON as specified storage file, as schema by default
  await workbook.SaveAsJsonAsync(storageFile, range);

  //Saves the Range to a JSON filestream, as schema by default
  MemoryStream stream = new MemoryStream();
  workbook.Version = ExcelVersion.Xlsx;
  await workbook.SaveAsJsonAsync(stream, range);
  Save(stream, "Excel-Range-To-JSON-filestream-as-schema-default.json");
}

//Save the Range stream as a file.

#region Setting output location
async void Save(Stream stream, string filename)
{
  stream.Position = 0;

  StorageFile stFile;
  if (!(Windows.Foundation.Metadata.ApiInformation.IsTypePresent("Windows.Phone.UI.Input.HardwareButtons")))
  {
    FileSavePicker savePicker = new FileSavePicker();
    savePicker.DefaultFileExtension = ".json";
    savePicker.SuggestedFileName = filename;
    savePicker.FileTypeChoices.Add("JSON Files", new List<string>() { ".json" });
    stFile = await savePicker.PickSaveFileAsync();
  }
  else
  {
    StorageFolder local = Windows.Storage.ApplicationData.Current.LocalFolder;
    stFile = await local.CreateFileAsync(filename, CreationCollisionOption.ReplaceExisting);
  }
  if (stFile != null)
  {
    Windows.Storage.Streams.IRandomAccessStream fileStream = await stFile.OpenAsync(FileAccessMode.ReadWrite);
    Stream st = fileStream.AsStreamForWrite();
    st.Write((stream as MemoryStream).ToArray(), 0, (int)stream.Length);
    st.Flush();
    st.Dispose();
    fileStream.Dispose();
  }
}
#endregion

A complete working example to convert range to JSON with schema in C# is present on this GitHub page.

Range to JSON without schema

The following code illustrates how to convert an Excel Custom Range to the JSON file or JSON file stream without schema.

C# [Cross-platform]

using (ExcelEngine excelEngine = new ExcelEngine())
{
	IApplication application = excelEngine.Excel;
	application.DefaultVersion = ExcelVersion.Xlsx;
	FileStream inputStream = new FileStream(Path.GetFullPath(@"Data/InputTemplate.xlsx"), FileMode.Open, FileAccess.Read);
	IWorkbook workbook = application.Workbooks.Open(inputStream);
	IWorksheet worksheet = workbook.Worksheets[0];

	//Custom range
	IRange range = worksheet.Range["A1:F100"];

	#region save as JSON
	//Saves the workbook to a JSON filestream, as schema by default
	FileStream outputStream = new FileStream(Path.GetFullPath("Output/Excel-Range-To-JSON-filestream-without-schema.json"), FileMode.Create, FileAccess.ReadWrite);
	workbook.SaveAsJson(outputStream, range, false);
	#endregion

	//Dispose streams
	outputStream.Dispose();
	inputStream.Dispose();

	#region Open JSON 
	//Open default JSON
	#endregion
}

C# [Windows-specific]

using(ExcelEngine excelEngine = new ExcelEngine())
{
  IApplication application = excelEngine.Excel;
  application.DefaultVersion = ExcelVersion.Xlsx;
  IWorkbook workbook = application.Workbooks.Open("Sample.xlsx", ExcelOpenType.Automatic);

  //Active worksheet
  IWorksheet worksheet = workbook.Worksheets[0];

  //Custom range
  IRange range = worksheet.Range["A2:A5"];

  //Saves the range to a JSON file without schema
  workbook.SaveAsJson("Excel-Range-To-JSON-without-schema.json", range, false);

  //Saves the range to a JSON filestream without schema
  FileStream stream = new FileStream("Excel-Range-To-JSON-filestream-without-schema.json", FileMode.Create);
  workbook.SaveAsJson(stream, range, false);
}

VB.NET [Windows-specific]

Using excelEngine As ExcelEngine = New ExcelEngine()
  Dim application As IApplication = excelEngine.Excel
  application.DefaultVersion = ExcelVersion.Xlsx
  Dim workbook As IWorkbook = application.Workbooks.Open("Sample.xlsx", ExcelOpenType.Automatic)

  'Active worksheet
  Dim worksheet As IWorksheet = workbook.Worksheets(0)

  'Custom range
  Dim range As IRange = worksheet.Range("A2:A5")

  'Saves the range to a JSON file without schema
  workbook.SaveAsJson("Excel-Range-To-JSON-without-schema.json", range, false)

  'Saves the range to a JSON filestream without schema
  Dim stream As FileStream = new FileStream("Excel-Range-To-JSON-filestream-without-schema.json", FileMode.Create)
  workbook.SaveAsJson(stream, range, false)
End Using

UWP

using (ExcelEngine excelEngine = new ExcelEngine())
{
  //Gets assembly
  Assembly assembly = typeof(App).GetTypeInfo().Assembly;

  //Gets input Excel document from embedded resource collection
  Stream inputStream = assembly.GetManifestResourceStream("Sample.xlsx");
  IWorkbook workbook = await excelEngine.Excel.Workbooks.OpenAsync(inputStream);
  IWorksheet worksheet = workbook.Worksheets[0];

  //Custom range
  IRange range = worksheet.Range["A2:A5"];

  //Initializes FileSavePicker
  FileSavePicker savePicker = new FileSavePicker();
  savePicker.SuggestedStartLocation = PickerLocationId.Desktop;
  savePicker.SuggestedFileName = "Excel-To-JSON-without-schema";
  savePicker.FileTypeChoices.Add("JSON Files", new List<string>() { ".json" });

  //Creates a storage file from FileSavePicker
  StorageFile storageFile = await savePicker.PickSaveFileAsync();

  //Saves the Range to a JSON as specified storage file without schema
  await workbook.SaveAsJsonAsync(storageFile, range, false);

  //Saves the Range to a JSON filestream without schema
  MemoryStream stream = new MemoryStream();
  workbook.Version = ExcelVersion.Xlsx;
  await workbook.SaveAsJsonAsync(stream, range, false);
  Save(stream, "Excel-Range-To-JSON-filestream-without-schema.json");
}

//Save the Range stream as a file.

#region Setting output location
async void Save(Stream stream, string filename)
{
  stream.Position = 0;

  StorageFile stFile;
  if (!(Windows.Foundation.Metadata.ApiInformation.IsTypePresent("Windows.Phone.UI.Input.HardwareButtons")))
  {
    FileSavePicker savePicker = new FileSavePicker();
    savePicker.DefaultFileExtension = ".json";
    savePicker.SuggestedFileName = filename;
    savePicker.FileTypeChoices.Add("JSON Files", new List<string>() { ".json" });
    stFile = await savePicker.PickSaveFileAsync();
  }
  else
  {
    StorageFolder local = Windows.Storage.ApplicationData.Current.LocalFolder;
    stFile = await local.CreateFileAsync(filename, CreationCollisionOption.ReplaceExisting);
  }
  if (stFile != null)
  {
    Windows.Storage.Streams.IRandomAccessStream fileStream = await stFile.OpenAsync(FileAccessMode.ReadWrite);
    Stream st = fileStream.AsStreamForWrite();
    st.Write((stream as MemoryStream).ToArray(), 0, (int)stream.Length);
    st.Flush();
    st.Dispose();
    fileStream.Dispose();
  }
}
#endregion

A complete working example to convert range to JSON without schema in C# is present on this GitHub page.