Deleting selected row from gridview no longer works?

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Hello everyone.

My current delete code used to work in a Gridview table but no longer, after I stuffed it into an UpdatePanel.

Basically, users will select one or multiple rows with a checkbox and then the selected rows will be deleted upon clicking a button.

This is my aspx code;

<asp:UpdatePanel ID="upl" runat="server">
    <Triggers>
        <asp:AsyncPostBackTrigger ControlID="btnSearch" EventName="serverclick" />
        <asp:AsyncPostBackTrigger ControlID="GvGrade" />
    </Triggers>
    <ContentTemplate>
        <asp:GridView ID="GvGrade" runat="server" AutoGenerateColumns="false" ClientIDMode="Static">
            <Columns>
                <asp:TemplateField HeaderText="Task ID" HeaderStyle-HorizontalAlign="Center">
                    <HeaderStyle Width="100" BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                    <ItemStyle HorizontalAlign="Center" />
                    <ItemTemplate>
                        <asp:Label ID="lblID" CssClass="lblID" runat="server" Text='<%# Eval("drug_id") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
            <Columns>
                <asp:TemplateField HeaderText="Drug Name" HeaderStyle-HorizontalAlign="Center">
                    <HeaderStyle Width="300" BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                    <ItemStyle HorizontalAlign="Center" />
                    <ItemTemplate>
                        <asp:Label ID="lblDrugName" CssClass="lblImageName" runat="server" Text='<%# Eval("drug_name") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
            <Columns>
                <asp:TemplateField HeaderText="Drug Description" HeaderStyle-HorizontalAlign="Center">
                    <HeaderStyle Width="500" BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                    <ItemStyle HorizontalAlign="Center" />
                    <ItemTemplate>
                        <asp:Label ID="lblDrugDescription" CssClass="lblImage" runat="server" Text='<%# Eval("drug_description") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
            <Columns>
                <asp:TemplateField HeaderText="Task Status" HeaderStyle-HorizontalAlign="Center">
                    <HeaderStyle Width="200" BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                    <ItemStyle HorizontalAlign="Center" />
                    <ItemTemplate>
                        <asp:Label ID="lblTaskStatus" CssClass="lblImage" runat="server" Text='<%# Eval("task_status") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
            <Columns>
                <asp:TemplateField HeaderText="Task Type" HeaderStyle-HorizontalAlign="Center">
                    <HeaderStyle Width="100" BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                    <ItemStyle HorizontalAlign="Center" />
                    <ItemTemplate>
                        <asp:Label ID="lblTaskType" CssClass="lblImage" runat="server" Text='<%# Eval("task_type") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
            <Columns>
                <asp:TemplateField HeaderText="Delete Tasks" ItemStyle-Width="100px" ItemStyle-HorizontalAlign="Center">
                    <HeaderStyle Width="100" BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                    <ItemStyle HorizontalAlign="Center" />
                    <ItemTemplate>
                        <asp:CheckBox ID="chkbox" runat="server" onclick="javascript:HighlightRow(this);" />
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
        </asp:GridView>
    </ContentTemplate>
</asp:UpdatePanel>

And the code-behind;

protected void showData()
{
    SqlDataAdapter da = new SqlDataAdapter("select * from Drug", con);
    DataSet ds = new DataSet();
    da.Fill(ds);
    GvGrade.DataSource = ds;
    GvGrade.DataBind();
}


protected void DeleteRecord(string drug_name)
{
    SqlConnection con = new SqlConnection(cs);
    SqlCommand com = new SqlCommand("delete from Drug where drug_name=@ID", con);
    com.Parameters.AddWithValue("@ID", drug_name);
    con.Open();
    com.ExecuteNonQuery();
    con.Close();
}

protected void BtnLogin_Click(object sender, EventArgs e)
{
    foreach (GridViewRow grow in GvGrade.Rows)
    {
        CheckBox chkbox = (CheckBox)grow.FindControl("chkbox");
        if (chkbox.Checked)
        {
            string drug_name = grow.Cells[1].Text;
            DeleteRecord(drug_name);
        }
    }
    //Displaying the Data in GridView
    showData();
}

What I have tried:

I had googled around and read something about re-binding the table after button postback but I don't think that is the issue. I have also tried updating the panel in the code-behind with upl.Update but it still doesn't work. What is happening here?

Posted 30-Jun-17 15:47pm

LuciusAvette

Updated 30-Jun-17 21:10pm

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Comments

Karthik_Mahalingam 30-Jun-17 22:30pm

where is the delete button?

LuciusAvette 30-Jun-17 23:05pm

My bad. The delete button is placed outside the update panel.



<asp:Button ID="BtnRegister" runat="server" class="btn btn-info" Text="Delete" OnClick="BtnLogin_Click" />

Karthik_Mahalingam 30-Jun-17 23:06pm

place it inside and try

LuciusAvette 30-Jun-17 23:15pm

Hi Karthik, placing it inside doesn't work.

Even if I create a new column on purpose with

<asp:PostBackTrigger ControlID="BtnRegister" />

it shows an error " A control with ID 'BtnRegister' could not be found for the trigger in UpdatePanel 'upl'.".

Karthik_Mahalingam 30-Jun-17 23:18pm

place it inside ContentTemplate

LuciusAvette 30-Jun-17 23:18pm

Yes, I have done this too. It's the same problem.

Karthik_Mahalingam 30-Jun-17 23:19pm

try
asp:AsyncPostBackTrigger

LuciusAvette 30-Jun-17 23:21pm

Using AsyncPostBackTrigger, I could see a PostBack firing but not when I use PostBackTrigger. But both doesn't work too.

Karthik_Mahalingam 30-Jun-17 23:27pm

what is the meaning of doesnt work ?
not firing the event?

LuciusAvette 30-Jun-17 23:31pm

By placing the button inside ContentTemplate like you said,
AsyncPostBackTrigger = Post back fires.
PostBackTrigger = No post back.

Doesn't work = Unable to delete selected row using checkbox.

Without UpdatePanel, I can delete rows. But now that I am using UpdatePanel, the delete no longer works.

Karthik_Mahalingam 30-Jun-17 23:45pm

then use AsyncPostBackTrigger

i have tested it, works fine.

LuciusAvette 30-Jun-17 23:46pm

But the delete selected row still does not work. This is the main problem :/

Karthik_Mahalingam 30-Jun-17 23:50pm

show the page load code

LuciusAvette 1-Jul-17 0:03am

protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
showData();
BtnRegister.Attributes.Add("onclick", "javascript:return DeleteConfirm()");
}

if (Convert.ToString(Session["role"]) == "Member")
{
Response.Redirect("LoginRedirect.aspx");
return;
}
}

Karthik_Mahalingam 1-Jul-17 0:07am

looks fine

LuciusAvette 1-Jul-17 0:09am

Yeah everything is fine. I can delete rows without using UpdatePanel. But if I do, I can't delete. I don't know why.

Karthik_Mahalingam 1-Jul-17 0:13am

this is wht i have tried

  
        <asp:ScriptManager ID="ScriptManager1" runat="server">
      <asp:UpdatePanel ID="upl" runat="server">
         
    <triggers>
        
        <asp:AsyncPostBackTrigger ControlID="GvGrade" />
           <asp:AsyncPostBackTrigger ControlID="BtnRegister" />
    
    <contenttemplate>
        <asp:Button ID="BtnRegister" runat="server" class="btn btn-info" Text="Delete" OnClick="BtnLogin_Click" />


        <asp:GridView ID="GvGrade" runat="server" AutoGenerateColumns="false" ClientIDMode="Static">
            <columns>
                <asp:TemplateField HeaderText="Task ID" HeaderStyle-HorizontalAlign="Center">
                    <HeaderStyle Width="100" BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                    <ItemStyle HorizontalAlign="Center" />
                    <itemtemplate>
                        <asp:Label ID="lblID" CssClass="lblID" runat="server" Text='<%# Eval("drug_id") %>'>
                    
                
            
            <columns>
                <asp:TemplateField HeaderText="Drug Name" HeaderStyle-HorizontalAlign="Center">
                    <HeaderStyle Width="300" BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                    <ItemStyle HorizontalAlign="Center" />
                    <itemtemplate>
                        <asp:Label ID="lblDrugName" CssClass="lblImageName" runat="server" Text='<%# Eval("drug_name") %>'>
                    
                
            
            <columns>
                <asp:TemplateField HeaderText="Drug Description" HeaderStyle-HorizontalAlign="Center">
                    <HeaderStyle Width="500" BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                    <ItemStyle HorizontalAlign="Center" />
                    <itemtemplate>
                        <asp:Label ID="lblDrugDescription" CssClass="lblImage" runat="server" Text='<%# Eval("drug_description") %>'>
                    
                
            
            <columns>
                <asp:TemplateField HeaderText="Task Status" HeaderStyle-HorizontalAlign="Center">
                    <HeaderStyle Width="200" BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                    <ItemStyle HorizontalAlign="Center" />
                    <itemtemplate>
                        <asp:Label ID="lblTaskStatus" CssClass="lblImage" runat="server" Text='<%# Eval("task_status") %>'>
                    
                
            
            <columns>
                <asp:TemplateField HeaderText="Task Type" HeaderStyle-HorizontalAlign="Center">
                    <HeaderStyle Width="100" BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                    <ItemStyle HorizontalAlign="Center" />
                    <itemtemplate>
                        <asp:Label ID="lblTaskType" CssClass="lblImage" runat="server" Text='<%# Eval("task_type") %>'>
                    
                
            
            <columns>
                <asp:TemplateField HeaderText="Delete Tasks" ItemStyle-Width="100px" ItemStyle-HorizontalAlign="Center">
                    <HeaderStyle Width="100" BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                    <ItemStyle HorizontalAlign="Center" />
                    <itemtemplate>
                        <asp:CheckBox ID="chkbox" runat="server"    />

Karthik_Mahalingam 1-Jul-17 0:13am

public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
                showData();
            }
        }
        protected void showData()
        {
            DataTable ds = new DataTable();
            ds.Columns.Add("drug_id");

            ds.Columns.Add("drug_name");
            ds.Columns.Add("drug_description");
            ds.Columns.Add("task_status");
            ds.Columns.Add("task_type");

            ds.Rows.Add(1, "a", "aaa", "aaaa", "aaaaaaaaaaaa");
            ds.Rows.Add(2, "b", "bb", "bbb", "bbbbbbbbbbbb");
            ds.Rows.Add(3, "ac", "cc", "ccc", "ccccccccccc");
            ds.Rows.Add(4, "d", "dd", "ddddd", "dddddddddddddd");
            
            GvGrade.DataSource = ds;
            GvGrade.DataBind();
        }


        protected void DeleteRecord(string drug_name)
        {
             
        }

        protected void BtnLogin_Click(object sender, EventArgs e)
        {
            foreach (GridViewRow grow in GvGrade.Rows)
            {
                CheckBox chkbox = (CheckBox)grow.FindControl("chkbox");
                if (chkbox.Checked)
                {
                    string drug_name = grow.Cells[1].Text;
                    DeleteRecord(drug_name);
                }
            }
            //Displaying the Data in GridView  
            showData();
        }
    }

LuciusAvette 1-Jul-17 0:17am

That's for populating the table with data. It's not what I want.

I want to remove selected row, Karthik.

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LuciusAvette · Accepted Answer · 2017-06-30T21:10:00

Solution 1

Fixed.

Seems like my code behind for "DeleteRecord" just dislikes "TemplateField" and prefers "BoundField".

Posted 30-Jun-17 21:10pm

LuciusAvette