How to access a dropdownlistcontrol in grideview?

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Hello
Iam trying to access a dropdownlist inside grideview but i alaways get null exeption

1-the aspx file

ASP

<pre><%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="Employee_Mangment.Default" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
        <div>   
            <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataSourceID="ObjectDataSource1" OnRowDeleted="GridView1_RowDeleted" DataKeyNames="ID" OnRowUpdated="GridView1_RowUpdated" OnRowDataBound="GridView1_RowDataBound">
                <Columns>
                    <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" />
                    <asp:BoundField DataField="ID" HeaderText="ID" SortExpression="ID" ReadOnly="true" />
                    <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />
                    <asp:TemplateField HeaderText="Education" SortExpression="Education">
                        <EditItemTemplate>
                            <asp:DropDownList ID="DropDownList1" runat="server" DataSourceID="ObjectDataSource2" DataTextField="EducationType" DataValueField="EducationType" SelectedValue='<%# Bind("Education") %>'>
                            </asp:DropDownList>
                            <asp:ObjectDataSource ID="ObjectDataSource2" runat="server" SelectMethod="GetEducations" TypeName="Employee_Mangment.Data.EducationDataAccess"></asp:ObjectDataSource>
                        </EditItemTemplate>
                        <ItemTemplate>
                            <asp:Label ID="Label1" runat="server" Text='<%# Bind("Education") %>'></asp:Label>
                        </ItemTemplate>
                    </asp:TemplateField>
                </Columns>
            </asp:GridView>
            <asp:Label ID="Label1" runat="server" Text="" Font-Bold="true"></asp:Label>
            <asp:Label ID="Label2" runat="server" Text="" Font-Bold="true"></asp:Label>
            <asp:ObjectDataSource ID="ObjectDataSource1" runat="server" SelectMethod="GetEmployees" TypeName="Employee_Mangment.Data.EmployeeDataAccess" UpdateMethod="UpdateEmployee" ConflictDetection="CompareAllValues" OldValuesParameterFormatString="Original_{0}" DeleteMethod="DeleteEmployee" OnDeleted="ObjectDataSource1_Deleted" OnUpdated="ObjectDataSource1_Updated">
                <DeleteParameters>
                    <asp:Parameter Name="Original_ID" Type="Int32" />
                    <asp:Parameter Name="Original_Name" Type="String" />
                    <asp:Parameter Name="Original_Education" Type="String" />
                </DeleteParameters>
                <UpdateParameters>
                    <asp:Parameter Name="Original_ID" Type="Int32" />
                    <asp:Parameter Name="Original_Name" Type="String" />
                    <asp:Parameter Name="Original_Education" Type="String" />
                    <asp:Parameter Name="Name" Type="String" />
                    <asp:Parameter Name="Education" Type="String" />
                </UpdateParameters>
            </asp:ObjectDataSource>

        </div> 
    </form>
</body>
</html>

2-the code for the accessing is

C#

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{

    if(e.Row.RowType == DataControlRowType.DataRow)
    {
          DropDownList drop =
             (DropDownList)GridView1.Rows[1].FindControl("DropDownList1");


    }
}

What I have tried:

i tried to access it in the

GridView1_RowDataBound()

using this method row proparty byt get null too

Posted 31-Mar-20 4:16am

Member 14479161

Updated 1-Apr-20 5:32am

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Comments

Richard MacCutchan 31-Mar-20 10:23am

Use the debugger to see what is in GridView1.Rows[1]. it may be that the GridView has not been initialised.

Member 14479161 31-Mar-20 15:07pm

getting null too

Richard MacCutchan 1-Apr-20 3:00am

What does that mean?

Member 14479161 1-Apr-20 6:07am

null exeption for the value that i attached GridView1.Rows[1] to it

Richard MacCutchan 1-Apr-20 6:37am

There is still no point in me trying to figure out what that is referring to. Do what I suggested yesterday and use your debugger to find out which actual item is null. Then work backwards to find out why it has not been initialised.

Maciej Los 31-Mar-20 11:19am

Try this (inside GridView1_RowDataBound method):

DropDownList drop = (DropDownList)e.Row.FindControl("DropDownList1");

Let me know if it was helpful.

Member 14479161 31-Mar-20 15:01pm

getting null too

1 solution

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Richard Deeming · Answer 1 · 2020-04-01T05:34:00

The list control is in the EditItemTemplate. Therefore, it will only exist if the row is in the edit state.

C#

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow && (e.Row.RowState & DataControlRowState.Edit) != 0)
    {
        DropDownList drop = (DropDownList)e.Row.FindControl("DropDownList1");
        ...
    }
}

GridViewRow.RowState Property (System.Web.UI.WebControls) | Microsoft Docs[^]