我无法确定此问题的错误位置。 我有一个具有Gridview的ASP.NET Master.Page Web应用程序。我使用jquery选择的插件作为EmptyDataTemplate中的下拉列表（如果有数据，则使用FooterControl）。
在初始化时，如果网格没有数据，则会填充下拉列表并正确显示。如果网格中有项目并且我删除了所有项目，那么没有数据，下拉列表不会显示任何数据。调用DataBound事件，DataTable中包含所有正确的数据。它必然会下拉。但是项目会出现在列表中。 这是我的标记：
<div id="DelegateGridWrapper">
<asp:GridView ID="DelegateInfoGridView" runat="server"
AutoGenerateColumns="false" Caption="Delegate Information"
CaptionAlign="Top" CssClass="grid" RowStyle-Wrap="true"
HorizontalAlign="Left" ShowFooter="true"
AllowPaging="true" PageSize="5" ShowHeaderWhenEmpty="false" onrowediting="DelegateInfoGridView_RowEditing"
onrowcancelingedit="DelegateInfoGridView_RowCancelingEdit" onrowdeleting="DelegateInfoGridView_RowDeleting"
onrowupdating="DelegateInfoGridView_RowUpdating"
ondatabound="DelegateInfoGridView_DataBound"
onrowcommand="DelegateInfoGridView_RowCommand">
<Columns>
<asp:TemplateField HeaderText="Recipient ID">
<ItemTemplate>
<asp:Label ID="deligvLblRecipientID" runat="server" Text='<%# Bind("RecipientID") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Delegate" ItemStyle-Wrap="false">
<ItemTemplate>
<asp:Label ID="deligvLblRecipientName" runat="server" Text='<%# Bind("RecipientName") %>'></asp:Label>
</ItemTemplate>
<FooterTemplate>
<asp:DropDownList ID="deligvDDLRecipientName" runat="server" ClientIDMode="Static"
data-placeholder="Choose delegate…" class="chosen-single">
</asp:DropDownList>
</FooterTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Active">
<ItemTemplate>
<asp:Label ID="deligvLblActive" runat="server" Text='<%# (Boolean.Parse(Eval("Active").ToString())) ? "Yes" : "No" %>'></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:DropDownList ID="deligvDDLActive" runat="server" Text='<%# (Boolean.Parse(Eval("Active").ToString())) ? "Yes" : "No" %>'>
<asp:ListItem>Yes</asp:ListItem>
<asp:ListItem>No</asp:ListItem>
</asp:DropDownList>
</EditItemTemplate>
<FooterTemplate>
<asp:DropDownList ID="deligvDDLActiveInsert" runat="server">
<asp:ListItem Selected="True">Yes</asp:ListItem>
<asp:ListItem>No</asp:ListItem>
</asp:DropDownList>
</FooterTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Action" ItemStyle-Wrap="false" ItemStyle-HorizontalAlign="Center">
<ItemTemplate>
<asp:Button ID="deligvEditButton" runat="server" CausesValidation="False" CommandName="Edit"
Text="Edit" CssClass="gridActionbutton">
</asp:Button>
<asp:Button ID="deligvDeleteButton" runat="server" CausesValidation="False" CommandName="Delete" ClientIDMode="Static"
Text="Delete" CssClass="gridActionbutton" OnClientClick="return confirm('Are you sure you want to delete this Delegate Information?')" >
</asp:Button>
</ItemTemplate>
<EditItemTemplate>
<asp:Button ID="deligvUpdateButton" runat="server" CausesValidation="False" CommandName="Update"
Text="Update" CssClass="gridActionbutton"></asp:Button>
<asp:Button ID="deligvCancelButton" runat="server" CausesValidation="False" CommandName="Cancel"
Text="Cancel" CssClass="gridActionbutton"></asp:Button>
</EditItemTemplate>
<FooterTemplate>
<asp:Button ID="deligvAddButton" runat="server" CommandName="Add" Text="Add Delegate" Width="90%" CausesValidation="false"
CssClass="gridActionbutton">
</asp:Button>
</FooterTemplate>
</asp:TemplateField>
</Columns>
<EmptyDataTemplate>
<tr>
<th>Recipient ID</th>
<th>Delegate</th>
<th>Active</th>
<th>Action</th>
</tr>
<tr>
<td colspan="4" style="text-align:center;">
No Delegates were found for you. Delegates can be added by clicking the 'Add Delegate' Button.
</td>
</tr>
<tr>
<td></td>
<td>
<asp:DropDownList ID="deligvDDLRecipientName" runat="server" ClientIDMode="Static"
data-placeholder="Choose delegate…" class="chosen-single">
</asp:DropDownList>
</td>
<td>
<asp:DropDownList ID="deligvDDLActiveInsert" runat="server">
<asp:ListItem Selected="True">Yes</asp:ListItem>
<asp:ListItem>No</asp:ListItem>
</asp:DropDownList>
</td>
<td>
<asp:Button ID="deligvAddButtonEmpty" runat="server" CommandName="Add" Text="Add Delegate" Width="90%" CausesValidation="false"
CssClass="gridActionbutton">
</asp:Button>
</td>
</tr>
</EmptyDataTemplate>
</asp:GridView>
这是我的DataBound事件：
protected void DelegateInfoGridView_DataBound(object sender, EventArgs e)
{
try
{
m_strUserID = CommonMethods.ParseUserID(User.Identity.Name);
//Get the Footer controls that have the new entry data
Control tFooterControls = getFooterControls(DelegateInfoGridView);
DropDownList ddlRecipientNames = tFooterControls.FindControl("deligvDDLRecipientName") as DropDownList;
m_strXmlTableData = m_pagingClient.GetAllPossibleDelegates(m_strUserID);
DataTable tdtAllDelegates = CommonMethods.ParseXML(m_strXmlTableData);
ddlRecipientNames.DataSource = tdtAllDelegates;
ddlRecipientNames.DataTextField = "RecipientName";
ddlRecipientNames.DataValueField = "RecipientID";
ddlRecipientNames.DataBind();
ddlRecipientNames.Items.Insert(0, new ListItem("", "0"));//This is needed for the jquery-chosen dropdown to add data-holder text
}
catch (Exception ex)
{
//TO DO: Response.Redirect("~/Error.aspx");
}
}
为什么下拉列表会在删除所有项目后显示项目，但如果最初在gridview中没有要显示的项目，则会正确显示？ 我尝试触发所选下拉列表的更新，但最初在检索数据之前调用。 我不知道代码隐藏中是否存在错误，或者我是否需要在javascript中添加内容。
感谢。
更新
问题不在于所选插件。我从DropDown列表中删除了属性，将其更改为“选定”样式，问题仍然存在。因此，在用户删除网格中的所有项目后，不会填充asp：DropDownList。但是如果网格初始化时没有任何项目，则DropDown会正确填充。
更新 我有一个建议是使用'RowDeleted'事件来绑定下拉列表。但是，事件没有解雇。我将事件添加到标记中：
onrowdeleted="DelegateInfoGridView_RowDeleted"
这是永远不会被调用的事件：
protected void DelegateInfoGridView_RowDeleted(object sender, GridViewDeletedEventArgs e)
{
try
{
m_strUserID = CommonMethods.ParseUserID(User.Identity.Name);
//Get the Footer controls that have the new entry data
Control tFooterControls = getFooterControls(DelegateInfoGridView);
DropDownList tddlRecipientNames = tFooterControls.FindControl("deligvDDLRecipientName") as DropDownList;
m_strXmlTableData = m_pagingClient.GetAllPossibleDelegates(m_strUserID);
DataTable tdtAllDelegates = CommonMethods.ParseXML(m_strXmlTableData);
tddlRecipientNames.DataSource = tdtAllDelegates;
tddlRecipientNames.DataTextField = "RecipientName";
tddlRecipientNames.DataValueField = "RecipientID";
tddlRecipientNames.DataBind();
tddlRecipientNames.Items.Insert(0, new ListItem("", "0"));//This is needed for the jquery-chosen dropdown to add data-holder text
}
catch (Exception ex)
{
//TO DO: Response.Redirect("~/Error.aspx");
}
}
它不会触发的RowDeleted事件有什么不同？
答案 0 :(得分：0)
问题是我正在检查FooterControl是否为空。如果是的话，我得到了EmptyTemplateData控件。删除所有行时，FooterControl不为null，但需要获取EmptyTemplateData控件。 所以，我改变逻辑以检查网格行计数＆gt; 0而不是null FooterControl。 这解决了问题..