HyperLinkDesigner.GetDesignTimeHtml 方法

定義

命名空間:

System.Web.UI.Design.WebControls

組件:

System.Design.dll

取得在設計階段用來呈現關聯控制項的標記。

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

public override string GetDesignTimeHtml ();

override this.GetDesignTimeHtml : unit -> string

Public Overrides Function GetDesignTimeHtml () As String

傳回

String

字串，包含在設計階段用來呈現關聯超連結控制項的標記。

範例

下列程式碼範例示範如何從 HyperLinkDesigner 類別衍生 CustomHyperLinkDesigner 類別。 如果 的原始值為 Text 空字串，則會覆寫 GetDesignTimeHtml 方法，以提供 屬性的預設值 Text (「」) 。 這可確保在設計階段會顯示相關聯的控制項。

此程式碼範例是針對 類別提供的較大範例的 HyperLinkDesigner 一部分。

// Derive the CustomHyperLinkDesigner from the HyperLinkDesigner.
public class CustomHyperLinkDesigner : HyperLinkDesigner
{
    // Override the GetDesignTimeHtml to set the CustomHyperLink Text 
    // property so that it displays at design time.
    public override string GetDesignTimeHtml()
    {
        CustomHyperLink hype = (CustomHyperLink)Component;
        string designTimeMarkup = null;

        // Save the original Text and note if it is empty.
        string text = hype.Text;
        bool noText = (text.Trim().Length == 0);

        try
        {
            // If the Text is empty, supply a default value.
            if (noText)
                hype.Text = "Click here.";

            // Call the base method to generate the markup.
            designTimeMarkup = base.GetDesignTimeHtml();
        }
        catch (Exception ex)
        {
            // If an error occurs, generate the markup for an error message.
            designTimeMarkup = GetErrorDesignTimeHtml(ex);
        }
        finally
        {
            // Restore the original value of the Text, if necessary.
            if (noText)
                hype.Text = text;
        }

        // If the markup is empty, generate the markup for a placeholder.
        if(designTimeMarkup == null || designTimeMarkup.Length == 0)
            designTimeMarkup = GetEmptyDesignTimeHtml();

        return designTimeMarkup;
    } // GetDesignTimeHtml
} // CustomHyperLinkDesigner

' Derive the CustomHyperLinkDesigner from the HyperLinkDesigner.
Public Class CustomHyperLinkDesigner
    Inherits HyperLinkDesigner

    ' Override the GetDesignTimeHtml to set the CustomHyperLink Text
    ' property so that it displays at design time.
    Public Overrides Function GetDesignTimeHtml() As String

        Dim hype As CustomHyperLink = CType(Component, CustomHyperLink)
        Dim designTimeMarkup As String = Nothing

        ' Save the original Text and note if it is empty.
        Dim text As String = hype.Text
        Dim noText As Boolean = (text.Trim().Length = 0)

        Try
            ' If the Text is empty, supply a default value.
            If noText Then
                hype.Text = "Click here."
            End If

            ' Call the base method to generate the markup.
            designTimeMarkup = MyBase.GetDesignTimeHtml()

        Catch ex As Exception
            ' If an error occurs, generate the markup for an error message.
            designTimeMarkup = GetErrorDesignTimeHtml(ex)

        Finally
            ' Restore the original value of the Text, if necessary.
            If noText Then
                hype.Text = text
            End If
        End Try

        ' If the markup is empty, generate the markup for a placeholder.
        If ((designTimeMarkup = Nothing) Or _
            (designTimeMarkup.Length = 0)) Then
            designTimeMarkup = GetEmptyDesignTimeHtml()
        End If

        Return designTimeMarkup

    End Function ' GetDesignTimeHtml
End Class

備註

方法 GetDesignTimeHtml 會產生相關聯 HyperLink 控制項的設計階段標記。 方法會先儲存 、 NavigateUrl 和 ImageUrl 屬性的本機複本 Text ，以及 Controls 子集合。 如果原始值為 null 或空白，則會提供這些屬性的預設值。 然後，方法 GetDesignTimeHtml 會呼叫 GetDesignTimeHtml 基底方法來產生標記，並視需要將屬性和子控制項集合還原至其原始值。

另請參閱

• HyperLink
• GetDesignTimeHtml()
• ControlDesigner