無法使用複合控件加載視圖狀態

我已經創建了一個組合控件，該控件根據名爲「類型」的其中一個屬性的值更改其中的控件。意圖是，一旦設置了「類型」屬性，它就不會再爲控件的生命週期而更改，因此作爲「類型」屬性值結果呈現的控件不應更改。無法使用複合控件加載視圖狀態

我已經覆蓋LoadViewState和SaveViewState方法的建議在許多互聯網上的帖子，但我仍然收到有關「無法加載ViewState」的錯誤。該控件將在第一次加載時適當渲染，但一旦發生回發，它就會生成「加載ViewState失敗」錯誤。

下面是合成控制代碼的一部分：

[Serializable] 
internal enum SearchPanelControlType 
{ 
    Label, 
    DropDownList, 
    TextBox 
} 
[Serializable] 
internal class SearchGridViewStateObject<T> where T : Bll.BaseCriteria 
{ 
    public T mySearchCriteria { get; set; } 
    public SearchGridType myType { get; set; } 
    public int myNumberOfChildrenPerRow { get; set; } 
    public object myBaseViewState { get; set; } 

    public SearchGridViewStateObject(T searchCriteria, SearchGridType type, int numberOfChildrenPerRow, object baseViewState) 
    { 
     mySearchCriteria = searchCriteria; 
     myType = type; 
     myNumberOfChildrenPerRow = numberOfChildrenPerRow; 
     myBaseViewState = baseViewState; 
    } 
} 
[Themeable(true)] 
[Serializable] 
public class SearchGrid<T> : CompositeControl 
    where T : Bll.BaseCriteria 
{ 
    #region Constructor 
    public SearchGrid() 
    { 
    } 
    #endregion 

    #region Private Fields 
    private MyCompanygridview myGridView; 
    private ObjectDataSource myObjectDataSource; 
    private Panel mySearchParametersPanel; 
    private Button mySearchButton; 
    private Button myClearSearchCriteriaButton; 
    private T mySearchCriteria; 
    //private SearchGridType myType = SearchGridType.Account; 
    private SearchGridType myType; 
    private int myNumberOfChildrenPerRow = 2; 
    private MyCompanygridviewSelectionType mySelectionType = MyCompanygridviewSelectionType.None; 
    private int mySelectColumnIndex = 0; 
    private int myPageSize = 10; 
    private int myPageIndex = 0; 
    private string myGridViewCssClass; 
    private string myCustomPagerButtonCssClass; 
    private string myCustomPagerTextBoxCssClass; 
    private string myRowCssClass; 
    private string myEmptyDataRowCssClass; 
    private string myPagerCssClass; 
    private string mySelectedRowCssClass; 
    private string myHeaderCssClass; 
    private string myAlternatingRowCssClass; 
    private string myDisabledRowCssClass; 
    private List<Guid> myGridViewDisabledValues = new List<Guid>(); 
    private List<Guid> myGridViewSelectedValues = new List<Guid>(); 
    private GridLines myGridLines = GridLines.None; 
    private string mySearchPanelButtonCssClass; 
    private string mySearchPanelTextBoxCssClass; 
    private string mySearchPanelDropDownListCssClass; 
    private string mySearchPanelLabelCssClass; 



    #endregion 

    #region Public Properties 
    /// <summary> 
    /// Gets or sets the search criteria. 
    /// </summary> 
    /// <value>The search criteria.</value> 
    public T SearchCriteria 
    { 
     get 
     { 
      return mySearchCriteria; 
     } 
     set 
     { 
      if (value != mySearchCriteria) 
      { 
       mySearchCriteria = value; 
       this.ChildControlsCreated = false; 
       this.EnsureChildControls(); 
      } 
     } 
    } 
    /// <summary> 
    /// Gets or sets the type of items that should be shown in the gridview. 
    /// </summary> 
    /// <summary> 
    /// Gets or sets the type of items that should be shown in the gridview. 
    /// </summary> 
    [Category("SearchGrid"), 
    Description("Gets or sets the type of items that should be shown in the grid view."), 
    DefaultValue(null)] 
    public SearchGridType Type 
    { 
     get 
     { 
      return myType; 
     } 
     set 
     { 
      if (value != myType) 
      { 
       myType = value; 
       this.ChildControlsCreated = false; 
       this.EnsureChildControls(); 
      } 
     } 

    } 
    [DefaultValue(MyCompanygridviewSelectionType.None), 
    Category("SearchGrid"), 
    Description("Indicates whether to use multiselection mode, single selection mode, or no selection mode.")] 
    public MyCompanygridviewSelectionType SelectionType 
    { 
     get 
     { 
      return mySelectionType; 
     } 
     set 
     { 
      mySelectionType = value; 
     } 
    } 
    #endregion 
    #region Overridden Methods 
    protected override void LoadViewState(object savedState) 
    { 
     SearchGridViewStateObject<T> vsObject = savedState as SearchGridViewStateObject<T>; 
     mySearchCriteria = vsObject.mySearchCriteria; 
     myType = vsObject.myType; 
     myNumberOfChildrenPerRow = vsObject.myNumberOfChildrenPerRow; 

     ClearChildViewState(); 
     this.ChildControlsCreated = false; 
     this.EnsureChildControls(); 

     base.LoadViewState(vsObject.myBaseViewState); 
    } 
    protected override object SaveViewState() 
    { 
     SearchGridViewStateObject<T> vsObject = new SearchGridViewStateObject<T>(mySearchCriteria, myType, myNumberOfChildrenPerRow, base.SaveViewState()); 
     return vsObject; 
    } 
    protected override void RecreateChildControls() 
    { 
     EnsureChildControls(); 
    } 
    protected override void CreateChildControls() 
    { 
     SearchGridParser parser = SearchGridParserFactory.GetParser(this.myType); 

     Controls.Clear(); 

     //Define the Search Parameters Panel 
     mySearchParametersPanel = new Panel(); 
     mySearchParametersPanel.ID = "spp" + Enum.GetName(typeof(SearchGridType), this.myType); 
     mySearchParametersPanel.DefaultButton = "btnSearch"; 
     mySearchParametersPanel.ScrollBars = ScrollBars.None; 
     parser.CreateSearchPanelControls(ref mySearchParametersPanel, CreateSearchPanelStyleDictionary()); 


     //Define Buttons 
     mySearchButton = new Button(); 
     mySearchButton.ID = "btnSearch"; 
     mySearchButton.Text = "Search"; 
     mySearchButton.CausesValidation = false; 
     mySearchButton.UseSubmitBehavior = false; 
     mySearchButton.Click += new EventHandler(mySearchButton_Click); 
     if (!string.IsNullOrEmpty(mySearchPanelButtonCssClass)) 
     { 
      mySearchButton.CssClass = mySearchPanelButtonCssClass; 
     } 

     myClearSearchCriteriaButton = new Button(); 
     myClearSearchCriteriaButton.ID = "btnClearSearchCriteria"; 
     myClearSearchCriteriaButton.Text = "Clear Search Criteria"; 
     myClearSearchCriteriaButton.CausesValidation = false; 
     myClearSearchCriteriaButton.UseSubmitBehavior = false; 
     myClearSearchCriteriaButton.Click += new EventHandler(myClearSearchCriteriaButton_Click); 
     if (!string.IsNullOrEmpty(mySearchPanelButtonCssClass)) 
     { 
      myClearSearchCriteriaButton.CssClass = mySearchPanelButtonCssClass; 
     } 

     mySearchParametersPanel.Controls.Add(mySearchButton); 
     mySearchParametersPanel.Controls.Add(myClearSearchCriteriaButton); 

     // Define the GridView 
     myGridView = new MyCompanygridview(); 
     myGridView.ID = "gv" + Enum.GetName(typeof(SearchGridType), this.myType); 
     myGridView.AutoGenerateColumns = false; 
     myGridView.DataKeyNames = new string[] { "ID" }; 
     myGridView.DataSourceID = "ods" + Enum.GetName(typeof(SearchGridType), this.myType); 
     myGridView.AllowSorting = true; 
     myGridView.Width = new System.Web.UI.WebControls.Unit("100%"); 
     myGridView.AllowPaging = true; 
     myGridView.EnableCustomPager = true; 
     myGridView.Sorted += new EventHandler(myGridView_Sorted); 
     myGridView.PageIndexChanged += new EventHandler(myGridView_PageIndexChanged); 
     myGridView.PageSizeChanged += new EventHandler(myGridView_PageSizeChanged); 
     myGridView.PageSizeChanging += new EventHandler(myGridView_PageSizeChanging); 
     myGridView.SelectionType = this.mySelectionType; 
     myGridView.SelectColumnIndex = this.mySelectColumnIndex; 
     myGridView.PageSize = this.myPageSize; 
     myGridView.PageIndex = this.myPageIndex; 
     myGridView.CssClass = this.myGridViewCssClass; 
     myGridView.CustomPagerButtonCssStyle = this.myCustomPagerButtonCssClass; 
     myGridView.CustomPagerTextBoxCssStyle = this.myCustomPagerTextBoxCssClass; 
     myGridView.RowStyle.CssClass = this.myRowCssClass; 
     myGridView.EmptyDataRowStyle.CssClass = this.myEmptyDataRowCssClass; 
     myGridView.PagerStyle.CssClass = this.myPagerCssClass; 
     myGridView.SelectedRowStyle.CssClass = this.mySelectedRowCssClass; 
     myGridView.HeaderStyle.CssClass = this.myHeaderCssClass; 
     myGridView.AlternatingRowStyle.CssClass = this.myAlternatingRowCssClass; 
     myGridView.DisabledRowCssClass = this.myDisabledRowCssClass; 
     myGridView.DisabledValues = this.myGridViewDisabledValues; 
     myGridView.SelectedValues = this.myGridViewSelectedValues; 
     myGridView.GridLines = this.myGridLines; 
     parser.CreateGridViewColumns(ref myGridView); 


     // Define the object data source 
     myObjectDataSource = new ObjectDataSource(); 
     myObjectDataSource.ID = "ods" + Enum.GetName(typeof(SearchGridType), this.myType); 
     myObjectDataSource.OldValuesParameterFormatString = "original_{0}"; 
     myObjectDataSource.SelectMethod = "GetList"; 
     myObjectDataSource.SelectCountMethod = "SelectCountForGetList"; 
     myObjectDataSource.TypeName = "MyCompany.DCO.MyProject.Bll." + Enum.GetName(typeof(SearchGridType), this.myType) + "Manager"; 
     myObjectDataSource.EnablePaging = true; 
     myObjectDataSource.StartRowIndexParameterName = "startRowIndex"; 
     myObjectDataSource.MaximumRowsParameterName = "maximumRows"; 
     myObjectDataSource.SortParameterName = "SortExpression"; 
     myObjectDataSource.Selecting += new ObjectDataSourceSelectingEventHandler(myObjectDataSource_Selecting); 
     myObjectDataSource.Selected += new ObjectDataSourceStatusEventHandler(myObjectDataSource_Selected); 


     // Add the defined controls 
     this.Controls.Add(myObjectDataSource); 
     this.Controls.Add(myGridView); 
     this.Controls.Add(mySearchParametersPanel); 

     parser.SetSearchPanelControls<T>(this.mySearchCriteria, ref mySearchParametersPanel); 

    } 

    protected override void Render(HtmlTextWriter writer) 
    { 
     AddAttributesToRender(writer); 

     writer.RenderBeginTag(HtmlTextWriterTag.Div); 

     mySearchParametersPanel.RenderControl(writer); 
     writer.RenderBeginTag(HtmlTextWriterTag.Br); 
     writer.RenderEndTag(); 

     myGridView.RenderControl(writer); 
     writer.RenderBeginTag(HtmlTextWriterTag.Br); 
     writer.RenderEndTag(); 

     myObjectDataSource.RenderControl(writer); 
     writer.RenderEndTag(); 
    } 
    #endregion 

}

下面是創建自定義控制「解析器」文件中的代碼：

class SearchGridParser_ApplicationFunction : SearchGridParser 
{ 
    internal override void CreateGridViewColumns(ref MyCompanygridview myGridView) 
    { 
     // Link Column 
     HyperLinkField linkColumn = new HyperLinkField(); 
     linkColumn.Text = "Edit"; 
     linkColumn.HeaderText = "ID"; 
     linkColumn.DataNavigateUrlFields = new string[] { "ID" }; 
     linkColumn.DataNavigateUrlFormatString = "~/AddEdit/ApplicationFunction/default.aspx?Action=Edit&ID={0}"; 
     myGridView.Columns.Add(linkColumn); 

     // Name Column 
     BoundField nameColumn = new BoundField(); 
     nameColumn.DataField = "Name"; 
     nameColumn.HeaderText = "Name"; 
     nameColumn.SortExpression = "Name"; 
     myGridView.Columns.Add(nameColumn); 

     // Description Column 
     BoundField descriptionColumn = new BoundField(); 
     descriptionColumn.DataField = "Description"; 
     descriptionColumn.HeaderText = "Description"; 
     descriptionColumn.SortExpression = "Description"; 
     myGridView.Columns.Add(descriptionColumn); 

     // Business Criticality Column 
     TemplateField businessCriticalityColumn = new TemplateField(); 
     businessCriticalityColumn.SortExpression = "BusinessCriticality"; 
     businessCriticalityColumn.HeaderText = "Criticality"; 
     businessCriticalityColumn.ItemTemplate = new LabelColumnGridViewTemplate(ListItemType.Item, "BusinessCriticality", "Name"); 
     myGridView.Columns.Add(businessCriticalityColumn); 

     // Disabled Column 
     CheckBoxField disabledColumn = new CheckBoxField(); 
     disabledColumn.DataField = "DisabledFlg"; 
     disabledColumn.HeaderText = "Disabled"; 
     disabledColumn.SortExpression = "DisabledFlg"; 
     myGridView.Columns.Add(disabledColumn); 

     // Agencies Column 
     TemplateField agenciesColumn = new TemplateField(); 
     agenciesColumn.HeaderText = "Agencies"; 
     agenciesColumn.ItemTemplate = new ChildObjectsGridViewTemplate(ListItemType.Item, 2, "Agencies", "Agency.Abbreviation"); 
     myGridView.Columns.Add(agenciesColumn); 

     // Applications Column 
     TemplateField applicationsColumn = new TemplateField(); 
     applicationsColumn.HeaderText = "Applications"; 
     applicationsColumn.ItemTemplate = new ChildObjectsGridViewTemplate(ListItemType.Item, 2, "Applications", "Application.Name"); 
     myGridView.Columns.Add(applicationsColumn); 
    } 

    internal override void CreateSearchPanelControls(ref Panel myPanel, Dictionary<SearchPanelControlType, string> myStyleDictionary) 
    { 
     if (myStyleDictionary == null) 
     { 
      myStyleDictionary = new Dictionary<SearchPanelControlType, string>(); 
     } 

     // Title 
     Literal myTitleStart = new Literal(); 
     myTitleStart.Text = "<h4>"; 

     Label myTitle = new Label(); 
     myTitle.Text = "Application Function:"; 
     myTitle.ID = "lblTitle"; 

     Literal myTitleEnd = new Literal(); 
     myTitleEnd.Text = "</h4>"; 



     // Begin Table 
     Table myTable = new Table(); 
     myTable.ID = "myTable"; 

     // Create First Row 
     TableRow myTableRow1 = new TableRow(); 
     myTableRow1.ID = "myTableRow1"; 

     // Search by Name 
     TableCell myNameLabelTableCell = new TableCell(); 
     myNameLabelTableCell.ID = "myNameLabelTableCell"; 
     Label myNameLabel = new Label(); 
     myNameLabel.ID = "lblName"; 
     myNameLabel.Text = "Name:"; 
     myNameLabel.AssociatedControlID = "txtName"; 
     if (myStyleDictionary.ContainsKey(SearchPanelControlType.Label)) 
     { 
      myNameLabel.CssClass = myStyleDictionary[SearchPanelControlType.Label]; 
     } 
     myNameLabelTableCell.Controls.Add(myNameLabel); 
     myTableRow1.Cells.Add(myNameLabelTableCell); 

     TableCell myNameUserInputTableCell = new TableCell(); 
     myNameUserInputTableCell.ID = "myNameUserInputTableCell"; 
     TextBox myNameTextBox = new TextBox(); 
     myNameTextBox.ID = "txtName"; 
     if (myStyleDictionary.ContainsKey(SearchPanelControlType.TextBox)) 
     { 
      myNameTextBox.CssClass = myStyleDictionary[SearchPanelControlType.TextBox]; 
     } 
     myNameUserInputTableCell.Controls.Add(myNameTextBox); 
     myTableRow1.Cells.Add(myNameUserInputTableCell); 


     // Search by Agency 
     TableCell myAgencyLabelTableCell = new TableCell(); 
     myAgencyLabelTableCell.ID = "myAgencyLabelTableCell"; 
     Label myAgencyLabel = new Label(); 
     myAgencyLabel.ID = "lblAgency"; 
     myAgencyLabel.Text = "Agency:"; 
     myAgencyLabel.AssociatedControlID = "ddlAgency"; 
     if (myStyleDictionary.ContainsKey(SearchPanelControlType.Label)) 
     { 
      myAgencyLabel.CssClass = myStyleDictionary[SearchPanelControlType.Label]; 
     } 
     myAgencyLabelTableCell.Controls.Add(myAgencyLabel); 
     myTableRow1.Cells.Add(myAgencyLabelTableCell); 

     TableCell myAgencyUserInputTableCell = new TableCell(); 
     myAgencyUserInputTableCell.ID = "myAgencyUserInputTableCell"; 
     DropDownList<AgencyCriteria> myAgencyDDL = new DropDownList<AgencyCriteria>(); 
     myAgencyDDL.Type = DropDownListType.Agency; 
     myAgencyDDL.ID = "ddlAgency"; 
     if (myStyleDictionary.ContainsKey(SearchPanelControlType.DropDownList)) 
     { 
      myAgencyDDL.CssClass = myStyleDictionary[SearchPanelControlType.DropDownList]; 
     } 
     myAgencyDDL.DisplayDisabled = true; 
     myAgencyDDL.EnableAnyOption = true; 
     myAgencyDDL.DataBind(); 
     myAgencyUserInputTableCell.Controls.Add(myAgencyDDL); 
     myTableRow1.Cells.Add(myAgencyUserInputTableCell); 


     myTable.Rows.Add(myTableRow1); 

     // Create Second row 
     TableRow myTableRow2 = new TableRow(); 
     myTableRow2.ID = "myTableRow2"; 


     // Search by BusinessCriticality 
     TableCell myBusinessCriticalityLabelTableCell = new TableCell(); 
     myBusinessCriticalityLabelTableCell.ID = "myBusinessCriticalityLabelTableCell"; 
     Label myBusinessCriticalityLabel = new Label(); 
     myBusinessCriticalityLabel.ID = "lblBusinessCriticality"; 
     myBusinessCriticalityLabel.Text = "Criticality:"; 
     myBusinessCriticalityLabel.AssociatedControlID = "ddlBusinessCriticality"; 
     if (myStyleDictionary.ContainsKey(SearchPanelControlType.Label)) 
     { 
      myBusinessCriticalityLabel.CssClass = myStyleDictionary[SearchPanelControlType.Label]; 
     } 
     myBusinessCriticalityLabelTableCell.Controls.Add(myBusinessCriticalityLabel); 
     myTableRow2.Cells.Add(myBusinessCriticalityLabelTableCell); 

     TableCell myBusinessCriticalityUserInputTableCell = new TableCell(); 
     myBusinessCriticalityUserInputTableCell.ID = "myBusinessCriticalityUserInputTableCell"; 
     DropDownList<LookupCodeCriteria> myBusinessCriticalityDDL = new DropDownList<LookupCodeCriteria>(); 
     myBusinessCriticalityDDL.Type = DropDownListType.LookupCode; 
     myBusinessCriticalityDDL.ID = "ddlBusinessCriticality"; 
     if (myStyleDictionary.ContainsKey(SearchPanelControlType.DropDownList)) 
     { 
      myBusinessCriticalityDDL.CssClass = myStyleDictionary[SearchPanelControlType.DropDownList]; 
     } 
     myBusinessCriticalityDDL.DisplayDisabled = true; 
     myBusinessCriticalityDDL.EnableAnyOption = true; 
     LookupCodeCriteria myBusinessCriticalityCriteria = new LookupCodeCriteria(); 
     myBusinessCriticalityCriteria.Type = LookupCodeType.BusinessCriticality; 
     myBusinessCriticalityDDL.OtherCriteria = myBusinessCriticalityCriteria; 
     myBusinessCriticalityDDL.DataBind(); 
     myBusinessCriticalityUserInputTableCell.Controls.Add(myBusinessCriticalityDDL); 
     myTableRow2.Cells.Add(myBusinessCriticalityUserInputTableCell); 

     // Search by DisabledFlg 
     TableCell myDisabledFlgLabelTableCell = new TableCell(); 
     myDisabledFlgLabelTableCell.ID = "myDisabledFlgLabelTableCell"; 
     Label myDisabledFlgLabel = new Label(); 
     myDisabledFlgLabel.ID = "lblDisabledFlg"; 
     myDisabledFlgLabel.Text = "Disabled:"; 
     myDisabledFlgLabel.AssociatedControlID = "ddlDisabledFlg"; 
     if (myStyleDictionary.ContainsKey(SearchPanelControlType.Label)) 
     { 
      myDisabledFlgLabel.CssClass = myStyleDictionary[SearchPanelControlType.Label]; 
     } 
     myDisabledFlgLabelTableCell.Controls.Add(myDisabledFlgLabel); 
     myTableRow2.Cells.Add(myDisabledFlgLabelTableCell); 

     TableCell myDisabledFlgUserInputTableCell = new TableCell(); 
     myDisabledFlgUserInputTableCell.ID = "myDisabledFlgUserInputTableCell"; 
     YesNoAnyDropDownList myDisabledFlgDDL = new YesNoAnyDropDownList(); 
     myDisabledFlgDDL.ID = "ddlDisabledFlg"; 
     if (myStyleDictionary.ContainsKey(SearchPanelControlType.DropDownList)) 
     { 
      myDisabledFlgDDL.CssClass = myStyleDictionary[SearchPanelControlType.DropDownList]; 
     } 
     myDisabledFlgDDL.DataBind(); 
     myDisabledFlgUserInputTableCell.Controls.Add(myDisabledFlgDDL); 
     myTableRow2.Cells.Add(myDisabledFlgUserInputTableCell); 

     myTable.Rows.Add(myTableRow2); 


     myPanel.Controls.Add(myTitleStart); 
     myPanel.Controls.Add(myTitle); 
     myPanel.Controls.Add(myTitleEnd); 
     myPanel.Controls.Add(myTable); 
    } 

    internal override void FillSearchCriteria<T>(T myCriteria, ref Panel myPanel) 
    { 
     ApplicationFunctionCriteria derivedCriteria = new ApplicationFunctionCriteria(); 
     if (myCriteria != null) 
     { 
      derivedCriteria = myCriteria as ApplicationFunctionCriteria; 
     } 

     // Name 
     TextBox myNameTextBox = (TextBox)myPanel.FindControl("myTable").FindControl("myTableRow1").FindControl("myNameUserInputTableCell").FindControl("txtName"); 
     if (!string.IsNullOrEmpty(myNameTextBox.Text.Trim())) 
     { 
      derivedCriteria.Name = myNameTextBox.Text.Trim(); 
     } 
     else 
     { 
      derivedCriteria.Name = string.Empty; 
     } 

     // AgencyID 
     DropDownList<AgencyCriteria> myAgencyDDL = (DropDownList<AgencyCriteria>)myPanel.FindControl("myTable").FindControl("myTableRow1").FindControl("myAgencyUserInputTableCell").FindControl("ddlAgency"); 
     Guid myAgencyID; 
     if (myAgencyDDL.SelectedValue.TryParseGuid(out myAgencyID)) 
     { 
      derivedCriteria.AgencyID = myAgencyID; 
     } 
     else 
     { 
      derivedCriteria.AgencyID = null; 
     } 

     // BusinessCriticalityID 
     DropDownList<LookupCodeCriteria> myBusinessCriticalityDDL = (DropDownList<LookupCodeCriteria>)myPanel.FindControl("myTable").FindControl("myTableRow2").FindControl("myBusinessCriticalityUserInputTableCell").FindControl("ddlBusinessCriticality"); 
     Guid myBusinessCriticalityID; 
     if (myBusinessCriticalityDDL.SelectedValue.TryParseGuid(out myBusinessCriticalityID)) 
     { 
      derivedCriteria.BusinessCriticalityID = myBusinessCriticalityID; 
     } 
     else 
     { 
      derivedCriteria.BusinessCriticalityID = null; 
     } 

     // DisabledFlg 
     YesNoAnyDropDownList myDisabledFlgDDL = (YesNoAnyDropDownList)myPanel.FindControl("myTable").FindControl("myTableRow2").FindControl("myDisabledFlgUserInputTableCell").FindControl("ddlDisabledFlg"); 
     bool myDisabledFlg; 
     if (bool.TryParse(myDisabledFlgDDL.SelectedValue, out myDisabledFlg)) 
     { 
      derivedCriteria.DisabledFlg = myDisabledFlg; 
     } 
     else 
     { 
      derivedCriteria.DisabledFlg = null; 
     } 

    } 

    internal override void SetSearchPanelControls<T>(T myCriteria, ref Panel myPanel) 
    { 
     ApplicationFunctionCriteria derivedCriteria = new ApplicationFunctionCriteria(); 
     if (myCriteria != null) 
     { 
      derivedCriteria = myCriteria as ApplicationFunctionCriteria; 
     } 

     // Name 
     TextBox myNameTextBox = (TextBox)myPanel.FindControl("myTable").FindControl("myTableRow1").FindControl("myNameUserInputTableCell").FindControl("txtName"); 
     myNameTextBox.Text = derivedCriteria.Name; 

     // AgencyID 
     DropDownList<AgencyCriteria> myAgencyDDL = (DropDownList<AgencyCriteria>)myPanel.FindControl("myTable").FindControl("myTableRow1").FindControl("myAgencyUserInputTableCell").FindControl("ddlAgency"); 
     if (derivedCriteria.AgencyID.HasValue) 
     { 
      myAgencyDDL.SelectedValue = derivedCriteria.AgencyID.ToString(); 
     } 
     else 
     { 
      myAgencyDDL.SelectedValue = "0"; 
     } 

     // BusinessCriticalityID 
     DropDownList<LookupCodeCriteria> myBusinessCriticalityDDL = (DropDownList<LookupCodeCriteria>)myPanel.FindControl("myTable").FindControl("myTableRow2").FindControl("myBusinessCriticalityUserInputTableCell").FindControl("ddlBusinessCriticality"); 
     if (derivedCriteria.BusinessCriticalityID.HasValue) 
     { 
      myBusinessCriticalityDDL.SelectedValue = derivedCriteria.BusinessCriticalityID.ToString(); 
     } 
     else 
     { 
      myBusinessCriticalityDDL.SelectedValue = "0"; 
     } 

     // DisabledFlg 
     YesNoAnyDropDownList myDisabledFlgDDL = (YesNoAnyDropDownList)myPanel.FindControl("myTable").FindControl("myTableRow2").FindControl("myDisabledFlgUserInputTableCell").FindControl("ddlDisabledFlg"); 
     if (derivedCriteria.DisabledFlg.HasValue) 
     { 
      myDisabledFlgDDL.SelectedValue = derivedCriteria.DisabledFlg.ToString(); 
     } 
     else 
     { 
      myDisabledFlgDDL.SelectedValue = "any"; 
     } 

    } 
}

這裏是關於代碼我用來測試控件的aspx頁面：

<html xmlns="http://www.w3.org/1999/xhtml" > 
<head runat="server"> 
    <title></title> 
</head> 
<body> 
    <form id="form1" runat="server"> 
    <div> 
     <asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder> 
    </div> 
    </form> 
</body> 
</html>

而代碼隱藏：

public partial class test : System.Web.UI.Page 
{ 
    protected void Page_Load(object sender, EventArgs e) 
    { 
     CustomWebControls.SearchGrid<AccountCriteria> myAppFuncGrid = new  MyCompany.DCO.MyProject.CustomWebControls.SearchGrid<AccountCriteria>(); 
     myAppFuncGrid.Type = MyCompany.DCO.MyProject.CustomWebControls.SearchGridType.Account; 
     myAppFuncGrid.SelectionType = MyCompany.DCO.Library.WebControls.MyCompanygridviewSelectionType.Multiple; 
     myAppFuncGrid.PageSize = 3; 
     PlaceHolder1.Controls.Add(myAppFuncGrid); 
    } 
}

我試過只把控件放在if（！Page.IsPostBack）中，但是它只是在回發時甚至不顯示控件。我究竟做錯了什麼？

UPDATE：因此，我已將此添加到複合控件：

protected override void OnInit(EventArgs e) 
{ 
this.CreateChildControls(); base.OnInit(e); 
}

現在我不再得到「無法加載視圖狀態」的錯誤，但似乎子控件的視圖狀態不跨回發保存。我的複合控件中的一個控件是一個啓用了分頁的gridview，當點擊下一頁時，它將轉到第二頁，但從不轉到第3頁或第4頁等等。但它會去「最後一頁」，「第一頁」沒有問題。但是下一頁和上一頁不能正常工作，但它也不會引發錯誤。想法？

來源

2010-10-18 Amanda Kitson