Annotation Events in Blazor SfPdfViewer Component

17 Jul 202615 minutes to read

Annotation events notify the application when annotations are added, selected, moved, resized, modified, or removed. Subscribe to these events by using the PdfViewerEvents tag inside the SfPdfViewer component.

Events list

The table below lists every annotation and signature events in the PdfViewerEvents tag.

Name	Description
AddSignature	Triggers when a signature is added to a page.
AnnotationAdded	Triggers when an annotation is added to a page.
AnnotationMouseover	Triggers when the mouse pointer moves over an annotation.
AnnotationMoved	Triggers when an annotation is moved on a page.
AnnotationPropertiesChanged	Triggers when annotation properties are modified.
AnnotationRemoved	Triggers when an annotation is removed from a page.
AnnotationResized	Triggers when an annotation is resized on a page.
AnnotationSelected	Triggers when an annotation is selected on a page.
AnnotationUnselected	Triggers when an annotation is unselected on a page.
ExportFailed	Triggers when an annotation export fails.
ExportStarted	Triggers when annotation export starts.
ExportSucceed	Triggers when annotation export succeeds.
ImportFailed	Triggers when an annotation import fails.
ImportStarted	Triggers when annotation import starts.
ImportSucceed	Triggers when annotation import succeeds.
MoveSignature	Triggers when a signature is moved on a page.
OnAnnotationDoubleClick	Triggers when an annotation is double-clicked.
RemoveSignature	Triggers when a signature is removed from a page.
ResizeSignature	Triggers when a signature is resized on a page.
SignaturePropertiesChange	Triggers when signature properties are changed on a page.
SignatureSelected	Triggers when a signature is selected on a page.
SignatureUnselected	Triggers when a signature is unselected on a page.

AddSignature event

The AddSignature event triggers when a signature is added to a page.

Event arguments

See AddSignatureEventArgs for properties such as Id (string), PageNumber (int), and Bounds (PdfBounds – the rectangle of the added signature in page coordinates).

The following example illustrates handling the AddSignature event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents AddSignature="@AddSignature"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task AddSignature(AddSignatureEventArgs args) 
    {
        Console.WriteLine($"Added signature ID: {args.Id}");
    }	 
}

AnnotationAdded event

The AnnotationAdded event triggers when an annotation is added to a page.

Event arguments

See AnnotationAddedEventArgs for details such as AnnotationId (string), AnnotationType (PdfAnnotationType), PageNumber (int), and Bounds (PdfBounds).

The following example illustrates handling the AnnotationAdded event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents AnnotationAdded="@AnnotationAdded"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task AnnotationAdded(AnnotationAddEventArgs args)
    {
        Console.WriteLine($"Added annotation ID: {args.AnnotationId}");
    }	 
}

AnnotationMouseover event

The AnnotationMouseover event triggers when the mouse pointer moves over an annotation.

Event arguments

See AnnotationMouseoverEventArgs for details such as AnnotationId (string), AnnotationType (PdfAnnotationType), PageNumber (int), and the mouse cursor position via X and Y (double, in page coordinates).

The following example illustrates handling the AnnotationMouseover event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents AnnotationMouseover="@AnnotationMouseover"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task AnnotationMouseover(AnnotationMouseoverEventArgs args)
    {
        Console.WriteLine($"Annotation Mouseover X: {args.X} and Y: {args.Y}");
    }
}

AnnotationMoved event

The AnnotationMoved event triggers when an annotation is moved on a page.

Event arguments

See AnnotationMovedEventArgs for details such as AnnotationId (string), PageNumber (int), PreviousBounds (PdfBounds), and Bounds (PdfBounds).

The following example illustrates handling the AnnotationMoved event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents AnnotationMoved="@AnnotationMoved"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task AnnotationMoved(AnnotationMoveEventArgs args)
    {
        Console.WriteLine($"Annotation current position: {args.CurrentPosition}");
    }	 
}

AnnotationPropertiesChanged event

The AnnotationPropertiesChanged event triggers when annotation properties are modified on a page.

Event arguments

See AnnotationPropertiesChangedEventArgs for details such as AnnotationId (string), PageNumber (int), the changed property names, and old/new values. The class also exposes boolean change flags such as IsColorChanged, IsOpacityChanged, IsThicknessChanged, IsFontFamilyChanged, IsFontSizeChanged, and IsTextChanged that you can inspect in the handler.

The following example illustrates handling the AnnotationPropertiesChanged event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents AnnotationPropertiesChanged="@AnnotationPropertiesChanged"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task AnnotationPropertiesChanged(AnnotationPropertiesChangeEventArgs args)
    {
        Console.WriteLine($"Is annotation color changed: {args.IsColorChanged}");
    }	 
}

AnnotationRemoved event

The AnnotationRemoved event triggers when an annotation is removed from a page.

Event arguments

See AnnotationRemovedEventArgs for details such as AnnotationId (string), AnnotationType (PdfAnnotationType), and PageNumber (int).

The following example illustrates handling the AnnotationRemoved event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents AnnotationRemoved="@AnnotationRemoved"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task AnnotationRemoved(AnnotationRemoveEventArgs args)
    {
        Console.WriteLine($"Removed annotation ID: {args.AnnotationId}");
    }	 
}

AnnotationResized event

The AnnotationResized event triggers when an annotation is resized on a page.

Event arguments

See AnnotationResizedEventArgs for details such as AnnotationId (string), PageNumber (int), PreviousBounds (PdfBounds), and Bounds (PdfBounds).

The following example illustrates handling the AnnotationResized event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents AnnotationResized="@AnnotationResized"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task AnnotationResized(AnnotationResizeEventArgs args)
    {
        Console.WriteLine($"Resized annotation ID: {args.AnnotationId}");
    }	 
}

AnnotationSelected event

The AnnotationSelected event triggers when an annotation is selected on a page.

Event arguments

See AnnotationSelectedEventArgs for details such as AnnotationId (string), AnnotationType (PdfAnnotationType), and PageNumber (int).

The following example illustrates handling the AnnotationSelected event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents AnnotationSelected="@AnnotationSelected"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task AnnotationSelected(AnnotationSelectEventArgs args)
    {
        Console.WriteLine($"Selected annotation ID: {args.AnnotationId}");
    }	 
}

AnnotationUnselected event

The AnnotationUnselected event triggers when an annotation is unselected on a page.

Event arguments

See AnnotationUnselectedEventArgs for details such as AnnotationId (string), AnnotationType (PdfAnnotationType), and PageNumber (int).

The following example illustrates handling the AnnotationUnselected event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents AnnotationUnselected="@AnnotationUnselected"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task AnnotationUnselected(AnnotationUnselectEventArgs args)
    {
        Console.WriteLine($"Unselected Annotation ID: {args.AnnotationId}");
    }	 
}

ExportFailed event

The ExportFailed event triggers when annotation export fails.

Event arguments

See ExportFailureEventArgs for the ErrorDetails (string) describing why the export failed.

The following example illustrates handling the ExportFailed event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents ExportFailed="@ExportFailed"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task ExportFailed(ExportFailureEventArgs args)
    {
        Console.WriteLine($"Error details: {args.ErrorDetails}");
    }	 
}

ExportStarted event

The ExportStarted event triggers when annotation export starts.

Event arguments

See ExportStartEventArgs for the FileName (string) of the file being exported. The export is triggered by the user’s Export annotations action in the toolbar.

The following example illustrates handling the ExportStarted event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents ExportStarted="@ExportStarted"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task ExportStarted(ExportStartEventArgs args)
    {
        Console.WriteLine("Export action started");
    }	 
}

ExportSucceed event

The ExportSucceed event triggers when annotation export succeeds.

Event arguments

See ExportSuccessEventArgs for details such as FileName (string, the name of the exported file) and the exported annotation data.

The following example illustrates handling the ExportSucceed event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents ExportSucceed="@ExportSucceed"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task ExportSucceed(ExportSuccessEventArgs args)
    {
        Console.WriteLine($"Exported File name: {args.FileName}");
    }	 
}

ImportFailed event

The ImportFailed event triggers when annotation import fails.

Event arguments

See ImportFailureEventArgs for the ErrorDetails (string) describing why the import failed.

The following example illustrates handling the ImportFailed event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents ImportFailed="@ImportFailed"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task ImportFailed(ImportFailureEventArgs args)
    {
        Console.WriteLine($"Error details: {args.ErrorDetails}");
    }	 
}

ImportStarted event

The ImportStarted event triggers when annotation import starts.

Event arguments

See ImportStartEventArgs for the FileName (string) of the file being imported. The import is triggered by the user’s Import annotations action in the toolbar.

The following example illustrates handling the ImportStarted event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents ImportStarted="@ImportStarted"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task ImportStarted(ImportStartEventArgs args)
    {
        Console.WriteLine("Import annotation started");
    }	 
}

ImportSucceed event

The ImportSucceed event triggers when annotation import succeeds.

Event arguments

See ImportSuccessEventArgs for the FileName (string) of the imported file.

The following example illustrates handling the ImportSucceed event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents ImportSucceed="@ImportSucceed"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task ImportSucceed(ImportSuccessEventArgs args)
    {
        Console.WriteLine("Annotation imported successfully");
    }	 
}

MoveSignature event

The MoveSignature event triggers when a signature is moved on a page.

Event arguments

See MoveSignatureEventArgs for details such as Id (string), PageNumber (int), PreviousBounds (PdfBounds), and Bounds (PdfBounds).

The following example illustrates handling the MoveSignature event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents MoveSignature="@MoveSignature"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task MoveSignature(MoveSignatureEventArgs args)
    {
        Console.WriteLine($"Moved Signature ID: {args.Id}");
    }	 
}

OnAnnotationDoubleClick event

The OnAnnotationDoubleClick event triggers when an annotation is double-clicked.

Event arguments

See AnnotationDoubleClickEventArgs for details such as AnnotationId (string), AnnotationType (PdfAnnotationType), PageNumber (int), and the mouse position (X, Y – double, in page coordinates).

The following example illustrates handling the OnAnnotationDoubleClick event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents OnAnnotationDoubleClick="@OnAnnotationDoubleClick"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task OnAnnotationDoubleClick(AnnotationDoubleClickEventArgs args)
    {
        Console.WriteLine($"Double-clicked annotation ID: {args.AnnotationId}");
    }	 
}

RemoveSignature event

The RemoveSignature event triggers when a signature is removed from a page.

Event arguments

See RemoveSignatureEventArgs for details such as Id (string) and PageNumber (int).

The following example illustrates handling the RemoveSignature event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents RemoveSignature="@RemoveSignature"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task RemoveSignature(RemoveSignatureEventArgs args)
    {
        Console.WriteLine($"Removed signature ID: {args.Id}");
    }	 
}

ResizeSignature event

The ResizeSignature event triggers when a signature is resized on a page.

Event arguments

See ResizeSignatureEventArgs for details such as Id (string), PageNumber (int), PreviousBounds (PdfBounds), and Bounds (PdfBounds).

The following example illustrates handling the ResizeSignature event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents ResizeSignature="@ResizeSignature"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task ResizeSignature(ResizeSignatureEventArgs args)
    {
        Console.WriteLine($"Resized signature ID: {args.Id}");
    }	 
}

SignaturePropertiesChange event

The SignaturePropertiesChange event triggers when signature properties are changed on a page.

Event arguments

See SignaturePropertiesChangeEventArgs for details such as Id (string), PageNumber (int), and the changed property values.

The following example illustrates handling the SignaturePropertiesChange event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents SignaturePropertiesChange="@SignaturePropertiesChange"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task SignaturePropertiesChange(SignaturePropertiesChangeEventArgs args)
    {
        Console.WriteLine($"Is stroke color changed: {args.IsStrokeColorChanged}");
    }	 
}

SignatureSelected event

The SignatureSelected event triggers when a signature is selected on a page.

Event arguments

See SignatureSelectEventArgs for details such as Id (string) and PageNumber (int).

The following example illustrates handling the SignatureSelected event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents SignatureSelected="@SignatureSelected"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task SignatureSelected(SignatureSelectEventArgs args)
    {
        Console.WriteLine($"Selected Signature ID: {args.Id}");
    }	 
}

SignatureUnselected event

The SignatureUnselected event triggers when a signature is unselected on a page.

Event arguments

See SignatureSelectEventArgs for details such as Id (string) and PageNumber (int).

The following example illustrates handling the SignatureUnselected event.

@using Syncfusion.Blazor.SfPdfViewer 

<SfPdfViewer2 DocumentPath="@DocumentPath" Height="100%" Width="100%"> 
    <PdfViewerEvents SignatureUnselected="@SignatureUnselected"></PdfViewerEvents>
</SfPdfViewer2>

@code{ 
    private string DocumentPath { get; set; } = "wwwroot/Data/PDF_Succinctly.pdf";
    private async Task SignatureUnselected(SignatureSelectEventArgs args)
    {
        Console.WriteLine($"Unselected Signature ID: {args.Id}");
    }	 
}

View sample in GitHub.

Annotation Events in Blazor SfPdfViewer Component

Events list

AddSignature event

Event arguments

AnnotationAdded event

Event arguments

AnnotationMouseover event

Event arguments

AnnotationMoved event

Event arguments

AnnotationPropertiesChanged event

Event arguments

AnnotationRemoved event

Event arguments

AnnotationResized event

Event arguments

AnnotationSelected event

Event arguments

AnnotationUnselected event

Event arguments

ExportFailed event

Event arguments

ExportStarted event

Event arguments

ExportSucceed event

Event arguments

ImportFailed event

Event arguments

ImportStarted event

Event arguments

ImportSucceed event

Event arguments

MoveSignature event

Event arguments

OnAnnotationDoubleClick event

Event arguments

RemoveSignature event

Event arguments

ResizeSignature event

Event arguments

SignaturePropertiesChange event

Event arguments

SignatureSelected event

Event arguments

SignatureUnselected event

Event arguments

See also