RadComboBox LoadOnDemand 方法在运行时不显示 RadComboBox 的 SelectedValue

Question

我在下面 link 关注 RadGrid 内的 RadComboBox 的 按需加载 功能。
Link: http://demos.telerik.com/aspnet-ajax/combobox/examples/populatingwithdata/autocompletesql/defaultcs.aspx
Inside RadComboBox 中的绑定取决于从 RadGrid 外部的 Outside RadComboBox 中选择的项目。即，如果 RadComboBox 外部有项目：A、B、C、D、E 等那么 Inside RadComboBox 中的绑定将是：A1 到 An、B1 到 Bn、C1-Cn 等，具体取决于从 Outside RadComboBox 中选择的项目。

现在我有 3 个问题：
1) 如何在 ItemRequested 事件下，在第 0 个索引处使用 c# 代码在 Inside ComboBox 中将默认文本写为 "Select Item"？
2) 在 Edit/Update 按钮点击时，RadComboBox 选择的值在运行时没有显示。我能够在调试模式下看到该值，但在运行时间它从未显示。
3) 上面行中的 RadComboBox 中的搜索功能在我这边没有按预期工作。
即，在 Demo 中，搜索是在 A1 到 A100（总记录）和 return msg Items A1-A8 out of A8 之间。 ...即，在所有项目 (A100) 中，它只到 A8。
在我这边，搜索在 A1 到 A50 (ItemsPerPage) 和 return msg Items A1 到 A50 out of A2000（总记录数） ....即，在所有项目 (A2000) 中，它变得 batch/page/ItemPerPage 明智，然后当我向下滚动时它显示更多搜索结果。
我不希望发生这种情况，我希望它的工作方式与在 Demo/Link 中进行搜索时的工作方式相同。

以下是我当前的代码：
C#代码：

protected void RGGSTAcCode_ItemDataBound(object sender, GridItemEventArgs e)
{
    if (e.Item is GridEditableItem && e.Item.IsInEditMode)
    {
        //bind dropdwon while "Add" 
        string CompanyCode = ddlCompany.SelectedValue.ToString();
        GridEditableItem item = (GridEditableItem)e.Item;

        if (!(e.Item is IGridInsertItem))
        {
            RadComboBox rcb = (RadComboBox)item.FindControl("ddlAccountCode");
            //Select particular dropdown value while "Edit"
            Label lblAcCode2 = item.FindControl("lblAcCode2") as Label;
            if (!string.IsNullOrEmpty(lblAcCode2.Text))
            {
                rcb.SelectedValue = Session["AccountDescription"].ToString();
                string selVal = rcb.SelectedValue;
            }
        }
    }        
}    
public DataTable GetAccCode(string CompanyCode)
{
    SqlConnection con = new SqlConnection(strcon);
    SqlCommand cmd = new SqlCommand("[Invoice].[usp_tbl_AccountCode_DL_Test]", con);
    cmd.CommandType = CommandType.StoredProcedure;
    cmd.Parameters.AddWithValue("@CompanyCode", CompanyCode);
    SqlDataAdapter da = new SqlDataAdapter(cmd);
    DataTable dt = new DataTable();
    try
    {
        con.Open();
        da.Fill(dt);
        con.Close();
    }
    catch (Exception ex)
    {
    }
    return dt;
}    
//#Load on Demand
private const int ItemsPerRequest = 50;

private static string GetStatusMessage(int offset, int total)
{
    if (total <= 0)
        return "No matches";

    return String.Format("Items <b>1</b>-<b>{0}</b> out of <b>{1}</b>", offset, total);
}    
protected void ddlAccountCode_ItemsRequested(object sender, RadComboBoxItemsRequestedEventArgs e)
{
    string c = ddlCompany.SelectedValue.ToString();

    DataTable dt = new DataTable();
    dt = GetAccCode(c);

    RadComboBox combo = (RadComboBox)sender;

    int itemOffset = e.NumberOfItems;
    int endOffset = Math.Min(itemOffset + ItemsPerRequest, dt.Rows.Count);
    e.EndOfItems = endOffset == dt.Rows.Count;

    for (int i = itemOffset; i < endOffset; i++)
    {    
        combo.Items.Add(new RadComboBoxItem(dt.Rows[i]["AccountDescription"].ToString(), dt.Rows[i]["AccountDescription"].ToString()));
    }

    e.Message = GetStatusMessage(endOffset, dt.Rows.Count);
}
protected void ddlAccountCode_SelectedIndexChanged(object sender, RadComboBoxSelectedIndexChangedEventArgs e)
{
    string a = e.Value;
    Session["AccountCodeID"] = a;

    string b = e.Text;
    Session["AccountDescription"] = b;
}

HTML代码：

<telerik:RadComboBox ID="ddlCompany" runat="server" Height="200" Width="240"
          DropDownWidth="310" EmptyMessage="- Select Product -" HighlightTemplatedItems="true" CausesValidation="false"
          Filter="Contains" AppendDataBoundItems="true" AllowCustomText="true" AutoPostBack="true"
          DataTextField="Title" DataValueField="Code" OnSelectedIndexChanged="ddlCompany_SelectedIndexChanged">
        </telerik:RadComboBox>

        <br />

        <telerik:RadAjaxPanel ID="RadAjaxPanel4" runat="server">
                <telerik:RadGrid ID="RGGSTAcCode" runat="server"
                   ShowFooter="True" GroupingEnabled="False" ShowStatusBar="true" EmptyDataText="No record available." 
                   AllowAutomaticInserts="False" AllowAutomaticUpdates="False" AllowAutomaticDeletes="true" 
                   OnNeedDataSource="RGGSTAcCode_NeedDataSource" OnItemDataBound="RGGSTAcCode_ItemDataBound" 
                   OnInsertCommand="RGGSTAcCode_InsertCommand" OnDeleteCommand="RGGSTAcCode_DeleteCommand" 
                   OnUpdateCommand="RGGSTAcCode_UpdateCommand" OnItemCommand="RGGSTAcCode_ItemCommand">
                  <mastertableview ShowHeadersWhenNoRecords="true" autogeneratecolumns="false" datakeynames="AccountCodeID" InsertItemDisplay="Top"
                    insertitempageindexaction="ShowItemOnCurrentPage" ShowFooter="True" CommandItemDisplay="Top" ClientIDMode="Static">                                   
                         <Columns> 
                             <telerik:GridEditCommandColumn ButtonType="ImageButton" UniqueName="EditCommandColumn"></telerik:GridEditCommandColumn> 

                             <telerik:GridTemplateColumn UniqueName="AccountCode" HeaderText="Account Code">
                                <ItemTemplate>
                                  <asp:Label ID="lblAcCode" runat="server" Text='<%# Eval("AccountCode")%>'></asp:Label>
                                </ItemTemplate>
                                <EditItemTemplate>
                                   <asp:Label ID="lblAcCode2" runat="server" Text='<%# Eval("AccountCode") + " - " + Eval("AccountDescription")%>' Visible="false"></asp:Label>

                                   <telerik:RadComboBox ID="ddlAccountCode" runat="server" Height="200" Width="240" DropDownWidth="310" HighlightTemplatedItems="true" CausesValidation="true"       
                                       OnItemsRequested="ddlAccountCode_ItemsRequested" ItemsPerRequest="10"
                                       EnableLoadOnDemand="True" ShowMoreResultsBox="true" EnableVirtualScrolling="true"
                                       AutoPostBack="true" OnSelectedIndexChanged="ddlAccountCode_SelectedIndexChanged"

                                       Filter="Contains" AppendDataBoundItems="true" DataTextField="AccountDescription" DataValueField="AccountCodeID">
                                   </telerik:RadComboBox>                                   

                                </EditItemTemplate>
                             </telerik:GridTemplateColumn>

                             <telerik:GridBoundColumn DataField="AccountDescription" HeaderText="Description" UniqueName="AccountDescription" SortExpression="AccountDescription" InsertVisiblityMode="AlwaysHidden" ReadOnly="true" ></telerik:GridBoundColumn>
                             <telerik:GridBoundColumn aggregate="SUM" DataField="Amount" HeaderText="Amount" FooterAggregateFormatString="Total : {0:###,##0.00}" DataFormatString="{0:n}" FooterStyle-BackColor="#ffc04c" UniqueName="Amount" SortExpression="Amount"></telerik:GridBoundColumn>
                             <telerik:GridBoundColumn DataField="Remark" HeaderText="IFCA Remark" UniqueName="Remark" SortExpression="Remark">

                             </telerik:GridBoundColumn>    

                             <telerik:GridButtonColumn ConfirmTextFormatString="Are you sure you want to Delete {0} Account Code?" ConfirmTextFields="AccountCodeID"
                             ConfirmDialogType="RadWindow" CommandName="Delete" Text="Delete" UniqueName="DeleteColumn"></telerik:GridButtonColumn>                                                                            
                      </Columns>
                      <EditFormSettings>
                         <EditColumn ButtonType="ImageButton" />
                      </EditFormSettings>
                      <CommandItemSettings AddNewRecordText="Add new record" RefreshText="Refresh"></CommandItemSettings>
                  </mastertableview>
                </telerik:RadGrid>      
        </telerik:RadAjaxPanel>

我无法解决以上3个问题。请回复。
请注意，我是 Telerik 的新手。提前致谢

Answer 1

以下代码解决了我的问题：
第二期（编辑时 RadComboBox 在运行时不显示 SelectedValue）：

protected void RGGSTAcCode_ItemDataBound(object sender, GridItemEventArgs e)
    {
        if (e.Item is GridEditableItem && e.Item.IsInEditMode)
        {
            //bind dropdwon while "Add" 
            string CompanyCode = ddlCompany.SelectedValue.ToString();
            GridEditableItem item = (GridEditableItem)e.Item;

            if (!(e.Item is IGridInsertItem))
            {
                RadComboBox rcb = (RadComboBox)item.FindControl("ddlAccountCode");

                //bind combobox in Edit mode from DB when using LoadOnDemand
                RadComboBoxItem rcbi = new RadComboBoxItem();
                rcbi.Text = ((DataRowView)e.Item.DataItem)["AccountCode"].ToString() + '-' + ((DataRowView)e.Item.DataItem)["AccountDescription"].ToString();
                rcbi.Value = ((DataRowView)e.Item.DataItem)["AccountCodeID"].ToString();
                rcb.Items.Add(rcbi);
                rcbi.DataBind();
            }
        }
    }

第三期解决方案：

    //#Load on Demand
        private const int ItemsPerRequest = 50;

        private static string GetStatusMessage(int offset, int total)
        {
            if (total <= 0)
                return "No matches";

            return String.Format("Items <b>1</b>-<b>{0}</b> out of <b>{1}</b>", offset, total);
        }

    public DataTable GetAccCode(string CompanyCode)
    {
        SqlConnection con = new SqlConnection(strcon);
        SqlCommand cmd = new SqlCommand("[Invoice].[usp_tbl_AccountCode_DL_Test]", con);
        cmd.CommandType = CommandType.StoredProcedure;
        cmd.Parameters.AddWithValue("@CompanyCode", CompanyCode);
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataTable dt = new DataTable();
        try
        {
            con.Open();
            da.Fill(dt);
            con.Close();
        }
        catch (Exception ex)
        {
        }
        return dt;
    }
    protected void ddlAccountCode_ItemsRequested(object sender, RadComboBoxItemsRequestedEventArgs e)
        {
            string c = ddlCompany.SelectedValue.ToString();

            DataTable dt = GetAccCode(c);
            DataView dv = new DataView(dt);
            string txt = e.Text;
            dv.RowFilter = string.Format("AccountDescription LIKE '%{0}%'", txt);       
            int a = dv.Count;
            if (dv.Count > 0)
            {
                dt = dv.ToTable();
            }

            RadComboBox combo = (RadComboBox)sender;

            int itemOffset = e.NumberOfItems;
            int endOffset = Math.Min(itemOffset + ItemsPerRequest, dt.Rows.Count);
            e.EndOfItems = endOffset == dt.Rows.Count;

            for (int i = itemOffset; i < endOffset; i++)
            {
                combo.Items.Add(new RadComboBoxItem(dt.Rows[i]["AccountDescription"].ToString(), dt.Rows[i]["AccountDescription"].ToString()));
            }

            if (!string.IsNullOrEmpty(e.Text))
            {
                int num = dv.Count;
                endOffset = dv.Count;
            }

            e.Message = GetStatusMessage(endOffset, dt.Rows.Count); 
        }
        //#End of 'Load on Demand'

RadComboBox LoadOnDemand 方法在运行时不显示 RadComboBox 的 SelectedValue

RadComboBox LoadOnDemand approach is not showing the SelectedValue of RadComboBox at runtime

c#

asp.net

telerik

radgrid

radcombobox