绑定dropdownlist返回null值

Question

我正在将数据库中的数据绑定到gridview组合框值。以下是gridview和rowdatabound事件的编码部分。

<asp:GridView ID="workingdaygrid" runat="server" 
            onrowdeleting="branchgrid_RowDeleting" 
            onrowediting="branchgrid_RowEditing" 
            onrowcancelingedit="branchgrid_RowCancelingEdit" 
            onrowupdating="branchgrid_RowUpdating" DataKeyNames="Workingday_id" 
            onpageindexchanged="workingdaygrid_PageIndexChanged" AllowPaging="True" 
            CellPadding="4" ForeColor="#333333" GridLines="None" 
            AutoGenerateColumns="False" onrowdatabound="workingdaygrid_RowDataBound">
        <AlternatingRowStyle BackColor="White" />
        <Columns>
            <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" CancelImageUrl="~/images/Cancel.jpg"
                               DeleteImageUrl="~/images/delete.jpg" EditImageUrl="~/images/Edit.jpg"
                               UpdateImageUrl="~/images/update.jpg" ButtonType="Image"/>
            <asp:BoundField DataField="Workingday_id" HeaderText="WorkingDayID" />
            <asp:BoundField DataField="Working_date" HeaderText="WorkingDayID" />
            <asp:BoundField DataField="Working_day" HeaderText="WorkingDayID" />
            <asp:TemplateField HeaderText="WorkingdayType">
            <ItemTemplate>
            <asp:Label runat="server" Text='<%# Eval("Workingday_type") %>'></asp:Label></ItemTemplate>
            <EditItemTemplate>
            <asp:DropDownList ID="Workingdaytype" runat="server" Width="100px">
            </asp:DropDownList>
            </EditItemTemplate>
            </asp:TemplateField>
        </Columns>
        <EditRowStyle BackColor="#2461BF" />
        <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
        <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
        <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
        <RowStyle BackColor="#EFF3FB" />
        <SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />
        <SortedAscendingCellStyle BackColor="#F5F7FB" />
        <SortedAscendingHeaderStyle BackColor="#6D95E1" />
        <SortedDescendingCellStyle BackColor="#E9EBEF" />
        <SortedDescendingHeaderStyle BackColor="#4870BE" />
    </asp:GridView>

行数据绑定事件代码为

protected void workingdaygrid_RowDataBound(object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                DropDownList dl = (DropDownList)e.Row.FindControl("Workingdaytype");
                DataTable worktype = inter.bindworkdaytype();
                dl.DataSource = worktype;
                dl.DataTextField = "Workingday_type";
                dl.DataValueField = "Time_id";
                dl.DataBind();
            }
        }

在下一行中，当使用defugger（f11）运行下一行时，它返回零值DropDownList dl=（DropDown列表）e.Row.FindControl（"工作日类型"）；

Answer 1

DropDownList位于EditItemTemplate内，因此只有当网格处于编辑模式时才可用。更改您的代码：

if (e.Row.RowType == DataControlRowType.DataRow)

到此：

if (e.Row.RowType == DataControlRowType.DataRow && workingdaygrid.EditIndex > -1)

它应该起作用。