如何在gridview中的Edittemplate中填充数据库中的选定值

'callout_status'表

case_detail表

现在我有一个带有下拉列表的gridview . 基本上，gridview显示来自case_detail表的数据，下拉列表显示来自callout_status表的数据 .

目前，我可以从数据库填充下拉列表 . 对于ItemTemplate，它可以显示数据库中的选定值 . 但我无法在Edittemplate中显示所选值，每次按下编辑按钮，db中的选定选项都不会显示 . 不知道该怎么做 . 非常感谢 .

aspx页面

<form id="form1" runat="server">
<div>

    <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" 
        AutoGenerateDeleteButton="True" AutoGenerateEditButton="True" DataKeyNames="id" 
        onrowcancelingedit="GridView1_RowCancelingEdit" 
        onrowdeleting="GridView1_RowDeleting" onrowediting="GridView1_RowEditing" 
        onrowupdating="GridView1_RowUpdating" BackColor="White" 
        BorderColor="White" BorderStyle="Ridge" BorderWidth="2px" CellPadding="3" 
        CellSpacing="1" GridLines="None" OnRowDataBound="gvItem_RowDataBound" >
        <Columns>

          <asp:TemplateField HeaderText="收方">
                <EditItemTemplate>
                    <asp:DropDownList ID="DropDownList3"  runat="server"  ></asp:DropDownList>
                </EditItemTemplate>
                <ItemTemplate>
                    <asp:Label ID="Label5" runat="server" Text='<%# Bind("receiver_status_id") %>'></asp:Label>
                </ItemTemplate>
            </asp:TemplateField> 
             <asp:TemplateField HeaderText="寄方">
                <EditItemTemplate>
                    <asp:DropDownList ID="DropDownList2"  runat="server"  ></asp:DropDownList>
                </EditItemTemplate>
                <ItemTemplate>
                    <asp:Label ID="Label4" runat="server" Text='<%# Bind("shipper_status_id") %>'></asp:Label>
                </ItemTemplate>
            </asp:TemplateField>

              <asp:TemplateField HeaderText="case_id">
                <EditItemTemplate>
                    <asp:TextBox ID="TextBox3" runat="server" Text='<%# Bind("case_id") %>'></asp:TextBox>
                </EditItemTemplate>
                <ItemTemplate>
                    <asp:Label ID="Label3" runat="server" Text='<%# Bind("case_id") %>'></asp:Label>
                </ItemTemplate>
            </asp:TemplateField>


            <asp:TemplateField HeaderText="Remarks">
                <EditItemTemplate>
                    <asp:TextBox ID="TextBox2" runat="server" Text='<%# Bind("remark") %>'></asp:TextBox>
                </EditItemTemplate>
                <ItemTemplate>
                    <asp:Label ID="Label2" runat="server" Text='<%# Bind("remark") %>'></asp:Label>
                </ItemTemplate>
            </asp:TemplateField>
        </Columns>
        <FooterStyle BackColor="#C6C3C6" ForeColor="Black" />
        <HeaderStyle BackColor="#4A3C8C" Font-Bold="True" ForeColor="#E7E7FF" />
        <PagerStyle BackColor="#C6C3C6" ForeColor="Black" HorizontalAlign="Right" />
        <RowStyle BackColor="#DEDFDE" ForeColor="Black" />
        <SelectedRowStyle BackColor="#9471DE" Font-Bold="True" ForeColor="White" />
        <SortedAscendingCellStyle BackColor="#F1F1F1" />
        <SortedAscendingHeaderStyle BackColor="#594B9C" />
        <SortedDescendingCellStyle BackColor="#CAC9C9" />
        <SortedDescendingHeaderStyle BackColor="#33276A" />
    </asp:GridView>

</div>
</form>

aspx.cs页面

protected void Page_Load(object sender, EventArgs e)
    {
         string connString = "Server=localhost;Database=cs_case;Uid=root;Pwd='';SslMode=none";

        MySqlConnection con = new MySqlConnection(connString);

        if (!Page.IsPostBack)
        {
            refreshdata();
        }

    }

    public void refreshdata()
    {
        string connString = "Server=localhost;Database=cs_case;Uid=root;Pwd='';SslMode=none";

        MySqlConnection con = new MySqlConnection(connString);

        MySqlCommand cmd = new MySqlCommand("select id, remark,case_id,shipper_status_id,receiver_status_id from case_detail", con);
        MySqlDataAdapter sda = new MySqlDataAdapter(cmd);
        DataTable dt = new DataTable();
        sda.Fill(dt);
        GridView1.DataSource = dt;
        GridView1.DataBind();

    }

    protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
    {
        GridView1.EditIndex = e.NewEditIndex;
        refreshdata();
    }
    protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        string connString = "Server=localhost;Database=cs_case;Uid=root;Pwd='';SslMode=none";
        MySqlConnection con = new MySqlConnection(connString);

        int id = Convert.ToInt16(GridView1.DataKeys[e.RowIndex].Values["id"].ToString());
        MySqlCommand cmd = new MySqlCommand("delete from case_detail where id = @id", con);
        cmd.Parameters.AddWithValue("@id", id);
        con.Open();
        cmd.ExecuteNonQuery();
        con.Close();
        refreshdata();

    }
    protected void GridView1_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
    {
        GridView1.EditIndex = -1;
        refreshdata();
    }
    protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        string connString = "Server=localhost;Database=cs_case;Uid=root;Pwd='';SslMode=none";

        MySqlConnection con = new MySqlConnection(connString);


        int id = Convert.ToInt16(GridView1.DataKeys[e.RowIndex].Values["id"].ToString());
        TextBox txtname = GridView1.Rows[e.RowIndex].FindControl("TextBox2") as TextBox;
        TextBox txtemail = GridView1.Rows[e.RowIndex].FindControl("TextBox3") as TextBox;
        DropDownList drpgender = GridView1.Rows[e.RowIndex].FindControl("DropDownList2") as DropDownList;
        DropDownList drpgender2 = GridView1.Rows[e.RowIndex].FindControl("DropDownList3") as DropDownList;

        MySqlCommand cmd = new MySqlCommand("update case_detail set remark=@remark, case_id=@case_id,shipper_status_id=@shipper_status_id,receiver_status_id=@receiver_status_id where id =@id", con);
        cmd.Parameters.AddWithValue("@remark", txtname.Text);
        cmd.Parameters.AddWithValue("@case_id", txtemail.Text);
        cmd.Parameters.AddWithValue("@shipper_status_id", drpgender.SelectedItem.Text);
        cmd.Parameters.AddWithValue("@receiver_status_id", drpgender2.SelectedItem.Text);

        cmd.Parameters.AddWithValue("@id", id);
        con.Open();
        cmd.ExecuteNonQuery();
        con.Close();
        refreshdata();

        GridView1.EditIndex = -1;
        refreshdata();


    }
//dropdown
    protected void gvItem_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            //1st dopdown
            var DropDownList1 = e.Row.FindControl("DropDownList2") as DropDownList;

            if (DropDownList1 != null)
            {
                var dt = new DataTable();
                using (var con = new MySqlConnection("Server=localhost;Database=cs_case;Uid=root;Pwd='';SslMode=none"))
                {
                    con.Open();
                   // var cmd = new MySqlCommand("Select * from callout_status where category ='shipper'", con);

                    var cmd = new MySqlCommand("Select * from callout_status where category ='shipper'", con);
                    var da = new MySqlDataAdapter(cmd);
                    da.Fill(dt);
                }

                DropDownList1.DataSource = dt;
                DropDownList1.DataTextField = "status";
                DropDownList1.DataValueField = "status";
                DropDownList1.DataBind();
                DropDownList1.Items.Insert(0, new ListItem("", "NA"));
            }
            //2nd dopdown

            var DropDownList3 = e.Row.FindControl("DropDownList3") as DropDownList;

            if (DropDownList3 != null)
            {
                var dt = new DataTable();
                using (var con = new MySqlConnection("Server=localhost;Database=cs_case;Uid=root;Pwd='';SslMode=none"))
                {
                    con.Open();
                    var cmd = new MySqlCommand("Select * from callout_status where category ='receiver'", con);
                    var da = new MySqlDataAdapter(cmd);
                    da.Fill(dt);
                }

                DropDownList3.DataSource = dt;
                DropDownList3.DataTextField = "status";
                DropDownList3.DataValueField = "status";
                DropDownList3.DataBind();
                var value = e.Row.DataItem.ToString();

                DataRowView dr = e.Row.DataItem as DataRowView;
                DropDownList3.SelectedValue = value; // you can use e.R


                DropDownList3.Items.Insert(0, new ListItem("", "NA"));


            }


        }
    }