下拉列表未在GridView中绑定 [英] Dropdown list not being binded in GridView

问题描述

大家好，



我的网格视图如下：

Hello everyone,

I have gridview as follows:

<asp:GridView ID="role_update" runat="server" AutoGenerateColumns="False" OnRowCancelingEdit="role_update_RowCancelingEdit"

                                OnRowEditing="role_update_RowEditing" OnRowUpdating="role_update_RowUpdating"

                                CssClass="GridView">
                                <Columns>
                                    <asp:TemplateField HeaderText="Name" HeaderStyle-HorizontalAlign="Center">
                                        <ItemTemplate>
                                            <asp:Label ID="lblname" runat="server" Text='<%# Bind("name") %>'></asp:Label>
                                        </ItemTemplate>
                                        <HeaderStyle HorizontalAlign="Center" />
                                        <ItemStyle HorizontalAlign="Center" />
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Code" HeaderStyle-HorizontalAlign="Center">
                                        <ItemTemplate>
                                            <asp:Label ID="lblcode" runat="server" Text='<%# Bind("code") %>'></asp:Label>
                                        </ItemTemplate>
                                        <HeaderStyle HorizontalAlign="Center" />
                                        <ItemStyle HorizontalAlign="Center" />
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Role" HeaderStyle-HorizontalAlign="Center">
                                        <ItemTemplate>
                                            <asp:Label ID="role_label" runat="server" Text='<%# Bind("role") %>'></asp:Label>
                                        </ItemTemplate>
                                        <HeaderStyle HorizontalAlign="Center" />
                                        <ItemStyle HorizontalAlign="Center" />
                                        <EditItemTemplate>
                                            <asp:DropDownList runat="server" ID="role_list" DataTextField="rolename" DataValueField="role" >
                                            </asp:DropDownList>
                                        </EditItemTemplate>
                                    </asp:TemplateField>
                                    <asp:CommandField HeaderText="Action" ShowEditButton="True" ButtonType="Button">
                                        <ControlStyle CssClass="btn" />
                                        <ItemStyle HorizontalAlign="Center" />
                                    </asp:CommandField>
                                </Columns>
                            </asp:GridView>

我想这样，当我点击编辑时，角色列下拉列表应该是当时绑定了，所以我在行编辑活动中尝试如下：

I want such that,when i click on edit,the role column dropdown list should be binded at that time,so i tried that in row editing event as follows:

protected void role_update_RowEditing(object sender, GridViewEditEventArgs e)
        {            
            role_update.EditIndex = e.NewEditIndex;
            GridViewRow row = role_update.Rows[e.NewEditIndex];
            DropDownList dl = (DropDownList)row.FindControl("role_list");
            SqlConnection conn = new SqlConnection();
            conn.ConnectionString=      System.Configuration.ConfigurationManager.ConnectionStrings["xyz"].ConnectionString;
            conn.Open();
            SqlCommand cmd = new SqlCommand("select  DISTINCT role from table", conn);
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataSet ds = new DataSet();
            da.Fill(ds);
            dl.DataSource = ds;
            dl.DataBind();
            conn.Close();
            rolebind();
        }

问题是，我在上面突出显示的行中得到对象引用错误，这意味着我得到null下拉，因为item_mplate中没有role_list ，它在edititemtemplate。



我的问题是如何在编辑时绑定下拉菜单？



我googled很多，但每个例子都显示在rowdatabound事件中的绑定，这对我来说是无用的（按照我的想法）。如果没有，那么如何实现呢？



任何帮助我会非常感激。

The problem is,i am getting object reference error at the line highlighted above,it means i am getting null dropdown as role_list is not there in itemtemplate,its in edititemtemplate.

My question is how to bind dropdown at time of editing?

I googled alot but every example shows binding in rowdatabound event,thats useless for me(as per as i think).If not,then how to accomplish that?

Any help would be really appreciated.

推荐答案

您正在使用错误的事件来绑定您的gridview。使用RowDataBound事件进行绑定。例如：

You are using wrong event to bind your gridview. Use RowDataBound event to bind. For example:

protected void YourGridView_RowDataBound(object sender, GridViewRowEventArgs e)
{
Control dl = e.Row.FindControl("yourDropDownList");
if (dl != null)
{
SqlConnection conn = new SqlConnection();
conn.ConnectionString=      System.Configuration.ConfigurationManager.ConnectionStrings["xyz"].ConnectionString;
conn.Open();
SqlCommand cmd = new SqlCommand("select  DISTINCT role from table", conn);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
dl.DataSource = ds;
dl.DataBind();
conn.Close();
rolebind();
}
}

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