GridView Error on Select: Object reference not set to an instance of an object

[JustRun]

I have a problem with the select option at the gridview and gonna pull my hair out cause it doesn't work at all.
Here is the Grid view code: I want to get the selected row when the user click "Select"

  <asp:GridView ID="grdDept" runat="server" AllowPaging="True" AllowSorting="True"
            AutoGenerateColumns="False" DataKeyNames="DocumentID" DataSourceID="sdsDepartment"
            Width="600px" CellPadding="4" ForeColor="#333333" GridLines="None">
            <Columns>
                <asp:TemplateField ShowHeader="False">
                    <EditItemTemplate>
                        <asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="True" CommandName="Update"
                            Text="Update"></asp:LinkButton>
                        <asp:LinkButton ID="LinkButton2" runat="server" CausesValidation="False" CommandName="Cancel"
                            Text="Cancel"></asp:LinkButton>
                    </EditItemTemplate>
                    <ItemTemplate>
                        <asp:LinkButton ID="btnEdit" runat="server" CausesValidation="False" CommandName="Edit"
                            Text="Edit"></asp:LinkButton>
                        <asp:LinkButton ID="btnSlct" runat="server" CausesValidation="False"
                            Text="Select" CommandName="Select"></asp:LinkButton>
                        <asp:LinkButton ID="btnDelete" runat="server" CausesValidation="False" CommandName="Delete"
                            Text="Delete"></asp:LinkButton>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="DocumentID" SortExpression="DocumentID">
                    <EditItemTemplate>
                        <asp:Label ID="Label1" runat="server" Text='<%# Eval("DocumentID") %>'></asp:Label>
                    </EditItemTemplate>
                    <ItemTemplate>
                        <asp:Label ID="Label1" runat="server" Text='<%# Bind("DocumentID") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="Department" SortExpression="DeptName">
                    <EditItemTemplate>
                        <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("DeptName") %>'></asp:TextBox>
                    </EditItemTemplate>
                    <ItemTemplate>
                        <asp:Label ID="lblDeptName" runat="server" Text='<%# Bind("DeptName") %>' Width="300px"></asp:Label>
                    </ItemTemplate>
                    <HeaderStyle Width="150px" />
                </asp:TemplateField>
            </Columns>
            <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
            <RowStyle BackColor="#F7F6F3" ForeColor="#333333" />
            <EditRowStyle BackColor="#999999" />
            <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
            <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
            <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
            <AlternatingRowStyle BackColor="White" ForeColor="#284775" />
        </asp:GridView>
 

In The Code Behind I tried many thing and all of them render the same error. "Object reference not set to an instance of an object".

 
    protected void grdDept_SelectedIndexChanging(object sender, GridViewSelectEventArgs e)
    {
        Label lblDeptName = (Label)grdDept.FindControl("lblDeptName");
        lblErr.Text = lblDeptName.Text;
    }  Also i tried this:       protected void grdDept_SelectedIndexChanging(object sender, GridViewSelectEventArgs e)
    {
        string strDept = grdDept.Rows[e.NewSelectedIndex].Cells[2].Text;
        lblErr.Text = strDept;
    }
 

[nateraaaa]

Could you post the server error you are receiving? The error should tell you what object is null.

Nathan

[JustRun]

This is the error :

Object reference not set to an instance of an object

Also i tried to catch the error but the catch got Nothing :_(

[Plater]

Did you set breakpoints and step through your code?

[JustRun]

No actually

I dont know How to do it

[Plater]

Place break point at the begining of your code behind function.
Hit F5 (to run in debug mode) then navigate the browser to the correct page that casues the error.

[JustRun]

There is no error but guess what:

I tried this to just test if the evnt work or not And I hot NOTHING displayed in the text box :

    protected void grdDept_SelectedIndexChanged(object sender, EventArgs e)
    {
        txtTest.Text = "Null";
    }
 

[Plater]

Somehow you have two controls with the same ID (when looking at your original post)
I cannot believe the program actually compiles without any errors/warnings about that.

[JustRun]

I've checked it well, and didn't find any conflict at the controls names.

Please tell me where is the conflict u r talking about?

Thanks

[Plater]

<EditItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%# Eval("DocumentID") %>'></asp:Label>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%# Bind("DocumentID") %>'></asp:Label>
</ItemTemplate>

[JustRun]

Yes they have the same name but there is no conflict cause each of them inside a template., They are not in the same template.

[Frinavale]

Yes they have the same name but there is no conflict cause each of them inside a template., They are not in the same template.

Are you using DataBind on the GridView in your PageLoad event?
If you do this all you will reset the data source for the GridView and delete any values that would have been entered by the end user during editing.

-Frinny

[JustRun]

Sorry Couldn't understand you!

Please Clarify more, But at any rate I bind my data through SqlDataSource

Thanks

[Frinavale]

Sorry Couldn't understand you!

Please Clarify more, But at any rate I bind my data through SqlDataSource

Thanks

Please post the code in your page load event.

[JustRun]

hI,
Sorry for the late reply, Here is the Code,
Note : The Commented Part is the part that not work and i want to fix it. but the uncommented part is the default Gridview this works fine.

            <asp:SqlDataSource ID="sdsAllDepts" runat="server" ConflictDetection="CompareAllValues"
                ConnectionString="Data Source=.;Initial Catalog=TimeSheet;Persist Security Info=True;User ID=sa;Password=sa"
                DeleteCommand="DELETE FROM [DepartmentTable] WHERE [DocumentID] = @original_DocumentID AND [DeptName] = @original_DeptName"
                InsertCommand="INSERT INTO [DepartmentTable] ([DeptName], [DocumentID]) VALUES (@DeptName, @DocumentID)"
                OldValuesParameterFormatString="original_{0}" ProviderName="System.Data.SqlClient"
                SelectCommand="SELECT [DeptName], [DocumentID] FROM [DepartmentTable] ORDER BY [DeptName]"
                UpdateCommand="UPDATE [DepartmentTable] SET [DeptName] = @DeptName WHERE [DocumentID] = @original_DocumentID AND [DeptName] = @original_DeptName" OnUpdated="sdsAllDepts_Updated">
                <DeleteParameters>
                    <asp:Parameter Name="original_DocumentID" Type="Object" />
                    <asp:Parameter Name="original_DeptName" Type="String" />
                </DeleteParameters>
                <UpdateParameters>
                    <asp:Parameter Name="DeptName" Type="String" />
                    <asp:Parameter Name="original_DocumentID" Type="Object" />
                    <asp:Parameter Name="original_DeptName" Type="String" />
                </UpdateParameters>
                <InsertParameters>
                    <asp:Parameter Name="DeptName" Type="String" />
                    <asp:Parameter Name="DocumentID" Type="Object" />
                </InsertParameters>
            </asp:SqlDataSource>
            <asp:ValidationSummary ID="ValidationSummary1" runat="server" />
<%--            <asp:GridView ID="grdDept" runat="server" AllowPaging="True" AllowSorting="True"
                AutoGenerateColumns="False" DataKeyNames="DocumentID"
                DataSourceID="sdsAllDepts" Width="685px" OnSelectedIndexChanging="grdDept_SelectedIndexChanging" CellPadding="4" ForeColor="#333333" GridLines="None">
                <Columns>
                    <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" ShowSelectButton="True">
                        <HeaderStyle Width="150px" />
                    </asp:CommandField>
                    <asp:TemplateField HeaderText="Department Name" SortExpression="DeptName">
                        <EditItemTemplate>
                            <table style="width: 535px">
                                <tr>
                                    <td style="width: 310px">
                                        &nbsp;<asp:TextBox ID="txtDeptName" runat="server" Text='<%# Bind("DeptName") %>' Width="300px" MaxLength="256"></asp:TextBox></td>
                                    <td style="width: 20px">
                                        <asp:RequiredFieldValidator
                                ID="RequiredFieldValidator1" runat="server" ControlToValidate="txtDeptName" ErrorMessage="Please enter a department name"
                                Text="*"></asp:RequiredFieldValidator><asp:RegularExpressionValidator ID="RegularExpressionValidator1"
                                    runat="server" ControlToValidate="txtDeptName" ErrorMessage="Department name should not allow Special Characters And Not Less Than 3 digits"
                                    ValidationExpression="\w+([\s]\w+)*">*</asp:RegularExpressionValidator></td>
                                    <td style="width: 235px">
                                        <asp:Label ID="Label12" runat="server" CssClass="formfont" ForeColor="White" Text="at least 3 digits with spaces"></asp:Label></td>
                                </tr>
                            </table>
                        </EditItemTemplate>
                        <ItemTemplate>
                            <asp:Label ID="Label1" runat="server" Text='<%# Bind("DeptName") %>' Width="300px"></asp:Label>
                        </ItemTemplate>
                    </asp:TemplateField>
                    <asp:BoundField DataField="DocumentID" HeaderText="DocumentID" ReadOnly="True" SortExpression="DocumentID"
                        Visible="False" />
                </Columns>
                <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                <RowStyle BackColor="#F7F6F3" ForeColor="#333333" />
                <EditRowStyle BackColor="#999999" />
                <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
                <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
                <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                <AlternatingRowStyle BackColor="White" ForeColor="#284775" />
                <EmptyDataTemplate>
                    <span style="color: darkslateblue">There is no data curruntly,<br />
                        If you want to add new departmnet, please follow</span>
                    <asp:HyperLink ID="HyperLink1" runat="server" NavigateUrl="~/administrator/NewDepartment.aspx">this link</asp:HyperLink>
                </EmptyDataTemplate>
            </asp:GridView>--%>
            <asp:GridView ID="grdDept" runat="server" AllowPaging="True" AllowSorting="True"
                AutoGenerateColumns="False" DataKeyNames="DocumentID"
                DataSourceID="sdsAllDepts" Width="600px" OnSelectedIndexChanging="grdDept_SelectedIndexChanging" CellPadding="4" ForeColor="#333333" GridLines="None">
                <Columns>
                    <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" ShowSelectButton="True" />
                    <asp:BoundField DataField="DeptName" HeaderText="Department Name" SortExpression="DeptName" />
                    <asp:BoundField DataField="DocumentID" HeaderText="DocumentID" ReadOnly="True" SortExpression="DocumentID"
                        Visible="False" />
                </Columns>
                <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                <RowStyle BackColor="#F7F6F3" ForeColor="#333333" />
                <EditRowStyle BackColor="#999999" />
                <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
                <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
                <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                <AlternatingRowStyle BackColor="White" ForeColor="#284775" />
                <EmptyDataTemplate>
                    <span style="color: darkslateblue">There is no data curruntly,<br />
                        If you want to add new departmnet, please follow</span>
                    <asp:HyperLink ID="HyperLink1" runat="server" NavigateUrl="~/administrator/NewDepartment.aspx">this link</asp:HyperLink>
                </EmptyDataTemplate>
            </asp:GridView>
            <br />
            <asp:Label ID="lblErr" runat="server" ForeColor="Red" Visible="False"></asp:Label><asp:HiddenField
                ID="txtDept" runat="server" />
            <br />
            <br />
            <asp:Label ID="lblDept" runat="server" Font-Bold="True"></asp:Label>
            <br />
            <br />
            <hr />
 

Here is the C# Code, Also this is the workng part And I've tried many thing to get the data from Template Gridview like: (rowcommand, rowdatabound, btnSlct_Click)

    protected void grdDept_SelectedIndexChanging(object sender, GridViewSelectEventArgs e)
    {
        lblErr.Visible = false;
        grdDetails.Visible = true;
        string dept = grdDept.Rows[e.NewSelectedIndex].Cells[1].Text;
        lblDept.Text = "Employees at '" + dept + "' department";
        txtDept.Value = dept;
    }
 

[Abhiraj Chauhan]

Any Idea which line is Causing it to say that..


Once you get the line number, you can then see which objects on that line are being dereferenced. The exception is thrown because one of the objects being dereferenced is not yet initialized.