Question

我试图在gridview中访问控件而没有运气。我搜索过互联网，没有任何例子可以帮助我。目前，我得到的错误消息是：“对象引用未设置为对象的实例”引用此行：lblErrors.Text = level.SelectedValue;

这是我背后的代码：

protected void setRecruitmentSchoolLevel(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        GridView recruitment = (GridView)sender;
        DropDownList level = (DropDownList)e.Row.FindControl("lstLevel");
        lblErrors.Text = level.SelectedValue;
    }
}

这是我的网站代码：

                        <asp:GridView ID="gridRecruitment" runat="server" DataSourceID="sourceRecruitment" Width="100%"
                        CellPadding="4" EnableModelValidation="True" ForeColor="#333333" OnRowDataBound="setRecruitmentSchoolLevel" 
                        GridLines="None" AutoGenerateColumns="False" AllowSorting="true" DataKeyNames="ID" EmptyDataText="No Recruitments">
                        <Columns>
                            <asp:HyperLinkField HeaderText="ID" DataTextField="ID" DataNavigateUrlFormatString="~/Admin/Recruit/recruit.aspx?ID={0}" DataNavigateURLFields="ID" Target="_blank" SortExpression="ID"/>
                            <asp:BoundField HeaderText="Class" DataField="GraduationYear" SortExpression="GraduationYear"/>
                            <asp:TemplateField HeaderText="Level" SortExpression="LevelName">
                                <ItemTemplate><%#Eval("LevelName") %></ItemTemplate>                                        
                                <EditItemTemplate>
                                    <asp:DropDownList ID="lstLevel" runat="server" DataSourceID="sourceLevels" DataTextField="Abbreviation" DataValueField="ID" SelectedValue='<%#Bind("Level") %>'/>
                                    <asp:SqlDataSource ID="sourceLevels" runat="server" ConnectionString="<%$ ConnectionStrings:DBCS %>" SelectCommand="SELECT Abbreviation, ID FROM Levels WHERE Recruiting = 'True' ORDER BY [Order] DESC"/>                                        
                                </EditItemTemplate>
                            </asp:TemplateField>
                            <asp:CommandField HeaderText="Commands" ShowEditButton="true" ShowDeleteButton="true" />
                        </Columns>
                    </asp:GridView>

Answer 1

看看这个问题的答案：how to access templatefield from code behind。回答者讨论了使用RowCreated和RowDataBound事件。

Answer 2

我认为你可以尝试这样的事情

protected void gridRecruitment_RowEditing(object sender, GridViewEditEventArgs e)
{
  GridView recruitment = (GridView)sender;
  GridViewRow row= recruitment.Rows[e.NewEditIndex];

  DropDownList level = (DropDownList)row.FindControl("lstLevel");
  lblErrors.Text = level.SelectedValue;

}

在gridview中访问控件

2 个答案: