Class CommandManager

Defines the collection of commands and the corresponding key gestures. It is responsible for managing routed commands.

Inheritance

System.Object

CommandManager

Namespace: Syncfusion.Blazor.Diagram

Assembly: Syncfusion.Blazor.dll

Syntax

public class CommandManager : ComponentBase

Remarks

CommandManager provides the support to define custom commands. The custom commands are executed when the specified key gesture is recognized.

Examples

<summary>
Notifies when to execute the custom keyboard commands .
</summary>
<remarks>
The following code illustrates how to create a custom command.
</remarks>
<example>
<code lang="Razor">
<![CDATA[
<SfDiagramComponent @ref="@diagram" Height="600px" Nodes="@nodes">
@* Initializing the custom commands*@
    <CommandManager Commands = "@command" Execute="@CommandExecute" CanExecute="@CanExe">
    </CommandManager>
</SfDiagramComponent>
@code
{
    // Reference to the diagram
    SfDiagramComponent diagram;
    DiagramObjectCollection<KeyboardCommand> command = new DiagramObjectCollection<KeyboardCommand>()
    {
        new Command()
        {
            Name = "CustomGroup",
            Gesture = new KeyGesture() { Key = DiagramKeys.G, KeyModifiers = KeyModifiers.Control }
        },
        new Command()
        {
            Name = "CustomUngroup",
            Gesture = new KeyGesture() { Key = DiagramKeys.U, KeyModifiers = KeyModifiers.Control }
        },
    };
    // Define the diagram's nodes collection
    DiagramObjectCollection<Node> nodes = new DiagramObjectCollection<Node>();
    public void CanExe(CommandKeyArgs args)
    {
        args.CanExecute = true;
    }
    public void CommandExecute(CommandKeyArgs args)
    {
        if (args.Gesture.KeyModifiers == KeyModifiers.Control && args.Gesture.Key == DiagramKeys.G)
        {
            //Custom command to group the selected nodes
            diagram.Group();
        }
        if (args.Gesture.KeyModifiers == KeyModifiers.Control && args.Gesture.Key == DiagramKeys.U)
        {
            Selector selector = diagram.SelectedItems;
            //Custom command to ungroup the selected items
            if (selector.Nodes.Count > 0 && selector.Nodes[0] is Group)
            {
                if ((selector.Nodes[0] as Group).Children.Length > 0)
                {
                    diagram.Ungroup();
                }
            }
        }
    }
}

Constructors

CommandManager()

Declaration

public CommandManager()

Properties

CanExecute

Determines whether this command can execute in its current state.

Declaration

public EventCallback<CommandKeyArgs> CanExecute { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<CommandKeyArgs>

Examples

<summary>
Notifies when to execute the custom keyboard commands .
</summary>
<remarks>
The following code illustrates how to create a custom command.
</remarks>
<example>
<code lang="Razor">
<![CDATA[
<SfDiagramComponent >
@* Initializing the custom commands*@
    <CommandManager CanExecute="@CanExe">
    </CommandManager>
</SfDiagramComponent>
@code
{
    public void CanExe(CommandKeyArgs args)
    {
        args.CanExecute = true;
    }
}

ChildContent

Gets or sets the child content of the Command Manager.

Declaration

public RenderFragment ChildContent { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.RenderFragment

Commands

Represents storing multiple command names with the corresponding command object.

Declaration

public DiagramObjectCollection<KeyboardCommand> Commands { get; set; }

Property Value

Type
DiagramObjectCollection<KeyboardCommand>

Examples

<summary>
Notifies when to execute the custom keyboard commands .
</summary>
<remarks>
The following code illustrates how to create a custom command.
</remarks>
<example>
<code lang="Razor">
<![CDATA[
<SfDiagramComponent >
    <CommandManager Commands = "@command" >
    </CommandManager>
</SfDiagramComponent>
@code
{
    DiagramObjectCollection<KeyboardCommand> command = new DiagramObjectCollection<KeyboardCommand>()
    {
        new Command()
        {
            Name = "CustomGroup",
            Gesture = new KeyGesture() { Key = DiagramKeys.G, Modifiers = ModifierKeys.Control }
        },
        new Command()
        {
            Name = "CustomUngroup",
            Gesture = new KeyGesture() { Key = DiagramKeys.U, Modifiers = ModifierKeys.Control }
        },
    };
}

CommandsChanged

Specifies the callback to trigger when the commands changes.

Declaration

public EventCallback<DiagramObjectCollection<KeyboardCommand>> CommandsChanged { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<DiagramObjectCollection<KeyboardCommand>>

Execute

Executes the command on the current command target.

Declaration

public EventCallback<CommandKeyArgs> Execute { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<CommandKeyArgs>

Examples

<summary>
Notifies when to execute the custom keyboard commands .
</summary>
<remarks>
The following code illustrates how to create a custom command.
</remarks>
<example>
<code lang="Razor">
<![CDATA[
<SfDiagramComponent >
@* Initializing the custom commands*@
    <CommandManager  Execute="@CommandExecute" >
    </CommandManager>
</SfDiagramComponent>
@code
{
    public void CommandExecute(CommandKeyArgs args)
    {
        if (args.Gesture.Modifiers == ModifierKeys.Control && args.Gesture.Key == DiagramKeys.G)
        {
            //Custom command to group the selected nodes
            diagram.Group();
        }
        if (args.Gesture.Modifiers == ModifierKeys.Control && args.Gesture.Key == DiagramKeys.U)
        {
            Selector selector = diagram.SelectedItems;
            //Custom command to ungroup the selected items
            if (selector.Nodes.Count > 0 && selector.Nodes[0] is Group)
            {
                if ((selector.Nodes[0] as Group).Children.Length > 0)
                {
                    diagram.Ungroup();
                }
            }
        }
    }
}

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()

OnInitializedAsync()

Method invoked when the component is ready to start.

Declaration

protected override Task OnInitializedAsync()

Returns

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