DataListDesigner.GetDesignTimeHtml Method

Definition

Namespace:

System.Web.UI.Design.WebControls

Assembly:

System.Design.dll

Gets the HTML used to represent the DataList control at design time.

public:
 override System::String ^ GetDesignTimeHtml();

public override string GetDesignTimeHtml ();

override this.GetDesignTimeHtml : unit -> string

Public Overrides Function GetDesignTimeHtml () As String

Returns

String

The HTML that is used to represent the DataList control at design time.

Examples

The following code example shows how to override the GetDesignTimeHtml method. It alters the appearance of the control on the design surface if the control's WebControl.Enabled property is true.

The code uses Try...Catch...Finally syntax to do the following:

• The Try section changes the values of the properties of the control.

• The Catch section catches any exceptions and sends them to the GetErrorDesignTimeHtml method.

• The Finally section sets the properties to their original values.

This code example is part of a larger example provided for the DataListDesigner class.

public override string GetDesignTimeHtml()
{
    string designTimeHtml = String.Empty;

    simpleGView = (SimpleGridView)Component;

    // Check the control's BorderStyle property to  
    // conditionally render design-time HTML.
    if (simpleGView.BorderStyle == BorderStyle.NotSet)
    {
        // Save the current property settings in variables.
        int oldCellPadding = simpleGView.CellPadding;
        Unit oldBorderWidth = simpleGView.BorderWidth;
        Color oldBorderColor = simpleGView.BorderColor;

        // Set properties and generate the design-time HTML.
        try
        {
            simpleGView.Caption = "SimpleGridView";
            simpleGView.CellPadding = 1;
            simpleGView.BorderWidth = Unit.Pixel(3);
            simpleGView.BorderColor = Color.Red;

            designTimeHtml = base.GetDesignTimeHtml();
        }
        catch (Exception ex)
        {
            // Get HTML from the GetErrorDesignTimeHtml 
            // method if an exception occurs.
            designTimeHtml = GetErrorDesignTimeHtml(ex);

            // Return the properties to their original values.
        }
        finally
        {
            simpleGView.CellPadding = oldCellPadding;
            simpleGView.BorderWidth = oldBorderWidth;
            simpleGView.BorderColor = oldBorderColor;
        }
    }
    else
    {
        designTimeHtml = base.GetDesignTimeHtml();
    }

    return designTimeHtml;
}

protected override string
    GetErrorDesignTimeHtml(System.Exception exc)
{
    return CreatePlaceHolderDesignTimeHtml(
        "ASPNET.Examples: An error occurred while rendering the GridView.");
}

Public Overrides Function GetDesignTimeHtml() As String
    Dim designTimeHtml As String = String.Empty

    simpleGView = CType(Component, SimpleGridView)

    ' Check the control's BorderStyle property to  
    ' conditionally render design-time HTML.
    If (simpleGView.BorderStyle = BorderStyle.NotSet) Then
        ' Save the current property settings in variables.
        Dim oldCellPadding As Integer = simpleGView.CellPadding
        Dim oldBorderWidth As Unit = simpleGView.BorderWidth
        Dim oldBorderColor As Color = simpleGView.BorderColor

        ' Set properties and generate the design-time HTML.
        Try
            simpleGView.Caption = "SimpleGridView"
            simpleGView.CellPadding = 1
            simpleGView.BorderWidth = Unit.Pixel(3)
            simpleGView.BorderColor = Color.Red

            designTimeHtml = MyBase.GetDesignTimeHtml()

        Catch ex As Exception
            ' Get HTML from the GetErrorDesignTimeHtml 
            ' method if an exception occurs.
            designTimeHtml = GetErrorDesignTimeHtml(ex)

            ' Return the properties to their original values.
        Finally
            simpleGView.CellPadding = oldCellPadding
            simpleGView.BorderWidth = oldBorderWidth
            simpleGView.BorderColor = oldBorderColor
        End Try

    Else
        designTimeHtml = MyBase.GetDesignTimeHtml()
    End If

    Return designTimeHtml
End Function

Protected Overrides Function _
    GetErrorDesignTimeHtml(ByVal exc As Exception) As String

    Return CreatePlaceHolderDesignTimeHtml( _
        "ASPNET.Examples: An error occurred while rendering the GridView.")

End Function

See also

• ControlDesigner
• ASP.NET Control Designers Overview