如何在后台代码中访问扩展Panel的自定义控件的公共属性？

Question

我想创建一个继承自Web控件“面板”的自定义控件。控件本身就像一个常规的Panel控件一样工作，但是我只能直接在.aspx页面上的控件上设置公共属性。我一直试图在Page_Load期间的代码中修改它们，但显然在页面生命周期中太晚了。当我尝试尽早做到这一点时，我得到一个空引用错误。有没有什么我可以在自定义控件中完成，以便在Page_Load（）期间可以修改它？

在ASPX，这与设置属性的控制（这工作正常）：

<cod:ContentOnDemandPanel LocationId="4" ID="codPanelLocation" runat="server"> 
    <p>This is some text that is in the panel</p> 
</cod:ContentOnDemandPanel> 

在后面的代码虽然（我尝试了生命周期的其他部分）。这是行不通的。

protected void Page_Load(object sender, EventArgs e) 
{ 
    codPanelLocation.LocationId = 22; 
    codPanelOfferingText.TelerikToolTipSkinName = "Black"; 
} 

任何帮助表示赞赏。

这里是我的课（去掉了一些东西，可能不适合大众消费）

命名空间Home.ContentOnDemand {

[ToolboxData("<{0}:ContentOnDemandPanel runat=server></{0}:ContentOnDemandPanel>")] 


public partial class ContentOnDemandPanel : Panel, INamingContainer 
{ 

    private ContentOnDemandDataSource _contentDataSource; 
    private RadToolTip _contentEditTooltip; 
    private ContentOnDemandItem _contentItem; 
    private int _contentItemId; 
    private bool _isEditMode; 

    private bool _isSharedContent; 
    private string _telerikToolTipSkinName; 
    private MasterWebDatabaseDataType _mwdbDataType; 
    private string _mwdbDataKeyValue; 
    private int _locationId; 
    private int _programId; 
    private int _areaOfStudyId; 
    private int _programOfferingId; 

    public ContentOnDemandPanel() 
    { 


    } 

    public override ControlCollection Controls 
    { 
     get 
     { 
      EnsureChildControls(); 
      return base.Controls; 
     } 
    } 

    protected override void CreateChildControls() 
    { 
     if (_isEditMode == false) 
     { 
      this._isEditMode = CODUtilities.isUserInEditMode(); 
     } 

     if (this._isEditMode) 
     { 
      Controls.Clear(); 

      if (_contentItemId > 0 && _contentDataSource == ContentOnDemandDataSource.CommonContent) 
      { 
       _contentItem = GetCommonContentItemByContentId(this._contentItemId); 
       if (_contentItem != null) 
       { 
        _contentEditTooltip = this.BuildRadToolTip(); 
        Controls.Add(_contentEditTooltip); 
       } 
      } 
      else 
      { 
       if (_contentDataSource == ContentOnDemandDataSource.MasterWeb) 
       { 
        _contentItem = GetCommonContentItemForMasterWeb(_mwdbDataType); 
        _contentEditTooltip = this.BuildRadToolTip(); 
        Controls.Add(_contentEditTooltip); 
       } 
      } 
     } 
    } 

    public void AddButtonsToToolTip(RadToolTip tooltip, ContentOnDemandItem item) 
    { 
     if (item != null) 
     { 
      if ((item != null) && ((item.EditItemPath.Length > 5) || (item.NewItemPath.Length > 5))) 
      { 
       Panel pnlButtonHolder = new Panel 
       { 
        CssClass = "cod-button-holder" 
       }; 
       HyperLink editButton = this.BuildEditButton(item.EditItemPath); 
       HyperLink addNewButton = this.BuildNewRecordButton(item.NewItemPath); 
       if (editButton != null) 
       { 
        pnlButtonHolder.Controls.Add(editButton); 
       } 
       if (addNewButton != null) 
       { 
        pnlButtonHolder.Controls.Add(addNewButton); 
       } 
       tooltip.Controls.AddAt(0, pnlButtonHolder); 
       this.CssClass = "cod-content-editable"; 
      } 
      else 
      { 
       this.makePanelNotCOD(); 
      } 
     } 
     else 
     { 
      this.makePanelNotCOD(); 
     } 
    } 

    private HyperLink BuildEditButton(string editPath) 
    { 
     if (editPath.Length < 5) 
     { 
      return null; 
     } 
     return new HyperLink { CssClass = "cod-button-edit", Text = "Edit Record", NavigateUrl = editPath, Target = "CMSWindow" }; 
    } 

    private HyperLink BuildNewRecordButton(string newRecordPath) 
    { 
     if (newRecordPath.Length < 5) 
     { 
      return null; 
     } 
     return new HyperLink { CssClass = "cod-button-new", Text = "Add New Record", NavigateUrl = newRecordPath, Target = "CMSWindow" }; 
    } 


    private RadToolTip BuildRadToolTip() 
    { 
     RadToolTip tt = new RadToolTip(); 

     AddButtonsToToolTip(tt,_contentItem); 
     return tt; 
    } 


    private ContentOnDemandItem GetCommonContentItemForMasterWeb(MasterWebDatabaseDataType dataType) 
    { 
     ContentOnDemandItem item = new ContentOnDemandItem(); 

     return item; 
    } 
    public static ContentOnDemandItem GetCommonContentItemByContentId(int contentId) 
    { 
     ContentOnDemandItem item = new ContentOnDemandItem(); 

     return item; 
    } 

    private void makePanelNotCOD() 
    { 
     this._isEditMode = false; 
     this.CssClass = ""; 
     this._contentEditTooltip = null; 
    } 

    protected override void Render(HtmlTextWriter writer) 
    { 
     this.RenderBeginTag(writer); 
     foreach (Control c in base.Controls) if (!c.Equals(_contentEditTooltip)) 
     c.RenderControl(writer); 
     if (_contentEditTooltip != null) 
     { 
      this._contentEditTooltip.RenderControl(writer); 
     } 
     this.RenderEndTag(writer); 
    } 

    // Properties 
    public ContentOnDemandDataSource ContentDataSource 
    { 
     get 
     { 
      return this._contentDataSource; 
     } 
     set 
     { 
      this._contentDataSource = value; 
     } 
    } 

    public ContentOnDemandItem ContentItem 
    { 
     get 
     { 
      return this._contentItem; 
     } 
     set 
     { 
      this._contentItem = value; 
     } 
    } 

    public bool IsEditMode 
    { 
     get { return _isEditMode; } 
     set { _isEditMode = value; } 
    } 

    public int ContentItemId 
    { 
     get 
     { 
      return this._contentItemId; 
     } 
     set 
     { 
      this._contentItemId = value; 
     } 
    } 

    public bool IsSharedContent 
    { 
     get 
     { 
      return this._isSharedContent; 
     } 
     set 
     { 
      this._isSharedContent = value; 
     } 
    } 
    public int ProgramId 
    { 
     get { return _programId; } 
     set { _programId = value; } 
    } 

    public int AreaOfStudyId 
    { 
     get { return _areaOfStudyId; } 
     set { _areaOfStudyId = value; } 
    } 

    public int ProgramOfferingId 
    { 
     get { return _programOfferingId; } 
     set { _programOfferingId = value; } 
    } 

    public MasterWebDatabaseDataType MwdbDataType 
    { 
     get { return _mwdbDataType; } 
     set { _mwdbDataType = value; } 
    } 

    public string MwdbDataKeyValue 
    { 
     get { return _mwdbDataKeyValue; } 
     set { _mwdbDataKeyValue = value; } 
    } 

    public int LocationId 
    { 
     get { return _locationId; } 
     set { _locationId = value; } 
    } 

    public string TelerikToolTipSkinName 
    { 
     get 
     { 
      return this._telerikToolTipSkinName; 
     } 
     set 
     { 
      this._telerikToolTipSkinName = value; 
     } 
    } 
} 

}

Answer 1

我建议的基础上，你的代码在上面，你把你的控制抽象出来了。创建一个包含标签（保存“T”文本）和两个用于添加/编辑的超链接的ASCX。

<％@控...％>

<div class="cod-content-editable"> 
    <asp:Label id="textLabel" runat="server" CssClass="Text"/> 
    <div class="cod-button-holder"> 
     <asp:HyperLink id="editLink" runat="server" Text="Edit" ... /> 
    </div> 
</div> 

等等等等，然后在你的代码，你可以直接连线属性的控件：

public class MyControl : UserControl 
{ 
    public string Text { get { return textLabel.Text; } set { textLabel.Text = value; } } 
    public Uri EditNavigateUri { get { return editLink.NavigateUri; } set { editLink.NavigateUri = value; } } 

    //...etc. 
}