Class DiagramHistoryManager

Notifies when changes are reverted or restored.

Inheritance

System.Object

DiagramHistoryManager

Namespace: Syncfusion.Blazor.Diagram

Assembly: Syncfusion.Blazor.dll

Syntax

public class DiagramHistoryManager : ComponentBase

Constructors

DiagramHistoryManager()

Initializes a new instance of the DiagramHistoryManager class.

Declaration

public DiagramHistoryManager()

Properties

CanRedo

Decides whether the history entry can be redo.

Declaration

public bool CanRedo { get; set; }

Property Value

Type
System.Boolean

CanUndo

Decides whether the history entry can be undo.

Declaration

public bool CanUndo { get; set; }

Property Value

Type
System.Boolean

ChildContent

Gets or Sets the child content for history manager

Declaration

public RenderFragment ChildContent { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.RenderFragment

CurrentEntry

Specifies the current entry object.

Declaration

public HistoryEntryBase CurrentEntry { get; set; }

Property Value

Type
HistoryEntryBase

HistoryAdding

Decides whether the changes are stored in the history or not.

Declaration

public EventCallback<HistoryAddingEventArgs> HistoryAdding { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<HistoryAddingEventArgs>

Examples

<SfDiagramComponent Width="800px" Height="800px">
    <DiagramHistoryManager HistoryAdding="OnHistoryAdding"></DiagramHistoryManager>
</SfDiagramComponent>
@code
{
    private void OnHistoryAdding(HistoryAddingEventArgs args)
    {
        args.Cancel = true;
    }
}

Redo

The method will be called when the custom entry is in the redo stage.

Declaration

public EventCallback<HistoryEntryBase> Redo { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<HistoryEntryBase>

Examples

<SfDiagramComponent Width="800px" Height="800px">
    <DiagramHistoryManager Redo="onCustomRedo"></DiagramHistoryManager>
</SfDiagramComponent>
@code
{
    private void onCustomRedo(HistoryEntryBase entry)
    {
        Node current = entry.UndoObject.Clone() as Node;
        (entry.UndoObject as Node).AdditionalInfo[(entry.UndoObject as Node).ID] = "Description";
        entry.RedoObject = current;
    }
}

StackLimit

Gets or sets the number of history entries that can be stored on the history list to limit undo, redo stack.

Declaration

public int StackLimit { get; set; }

Property Value

Type
System.Int32

Examples

<SfDiagramComponent Height="900px">
    <DiagramHistoryManager StackLimit="@stack" ></DiagramHistoryManager>
</SfDiagramComponent>

Undo

The method will be called when the custom entry is in undo stage.

Declaration

public EventCallback<HistoryEntryBase> Undo { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<HistoryEntryBase>

Examples

<SfDiagramComponent Width="800px" Height="800px">
    <DiagramHistoryManager Undo="onCustomUndo"></DiagramHistoryManager>
</SfDiagramComponent >
@code
{
    private void onCustomUndo(HistoryEntryBase entry)
    {
        (entry.RedoObject) = entry.UndoObject.Clone() as Node;
        (entry.UndoObject as Node).AdditionalInfo[(entry.UndoObject as Node).ID] = "Start";
    }
}

Methods

BuildRenderTree(RenderTreeBuilder)

Declaration

protected override void BuildRenderTree(RenderTreeBuilder __builder)

Parameters

Type	Name	Description
Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder	__builder

Dispose()

This method releasing all unmanaged resources.

Declaration

public void Dispose()

EndGroupAction()

Used to intimate the group action is end

Declaration

public void EndGroupAction()

Examples

//End the grouping of changes
diagram.EndGroupAction();

OnAfterRenderAsync(Boolean)

Method invoked after each time the component has been rendered.

Declaration

protected override Task OnAfterRenderAsync(bool firstRender)

Parameters

Type	Name	Description
System.Boolean	firstRender	Set to true for the first time component rendering, otherwise gets false.

Returns

Type	Description
System.Threading.Tasks.Task	A System.Threading.Tasks.Task representing any asynchronous operation.

OnInitializedAsync()

This method is invoked when the component is ready to start.

Declaration

protected override Task OnInitializedAsync()

Returns

Type
System.Threading.Tasks.Task

OnParametersSetAsync()

Method invoked when any changes in component state occur.

Declaration

protected override Task OnParametersSetAsync()

Returns

Type	Description
System.Threading.Tasks.Task	="Task".

StartGroupAction()

History allows you to revert or restore multiple changes through a single undo/redo command. It is used to start the grouping of changes.

Declaration

public void StartGroupAction()

Examples

//Start the grouping of changes 
diagram.StartGroupAction();