asp.net editable gridview "no data found" row causes issue after postback - asp.net

Question

I have a simple problem with my gridview. It is an editable gridview which allows inserting, updating and deleting rows. It is bound to a datatable. I store the datatable in the viewstate and bind the datatable on page_load for every postback. There is no column order or paging and I only have a few records on this gridview. When there is no data to display, I add an empty message text like "no data found" manually to grid. It is okey for the first page_load. But after postback, this text disappears, but the row is still there. And the main problem is the row has "edit" and "delete" command columns after postback. This row should not have edit or delete columns after postback. It works really fine before postback.
This problem never happens if there is at least one row in gridview.
If I have at least one row, then if I add more rows: No problem
If I have the empty grid, then I add a row (before any postback for example combobox value change): No problem
If I have the empty grid: then I do a postback by changing a value in a combobox, then "no rows found" message in the grid disappearing and there is an extra row in the grid which has no text and has edit and delete columns
If I have the grid with that unwanted row, then I add a row to that gridview: The unwanted row is going away and new row appearing on the grid. No problem
So the only problem is that extra row which is appearing after postback.
Code details are below. Please help me with this silly problem. I couldnt solve it for days.
ASPX:
<asp:GridView ID="grdTerminals" runat="server"
AutoGenerateColumns="False" DataKeyNames="TRM_ID"
OnRowCancelingEdit="grdTerminals_RowCancelingEdit"
OnRowDataBound="grdTerminals_RowDataBound"
OnRowEditing="grdTerminals_RowEditing"
OnRowUpdating="grdTerminals_RowUpdating" ShowFooter="True"
OnRowCommand="grdTerminals_RowCommand"
OnRowDeleting="grdTerminals_RowDeleting"
HeaderStyle-BackColor="#73be1e" HeaderStyle-ForeColor="Window" HeaderStyle-Font-Bold="true" Width="500px" HeaderStyle-Height="30">
<Columns>
<asp:TemplateField HeaderText="Terminal" HeaderStyle-HorizontalAlign="Left">
<EditItemTemplate>
<asp:DropDownList ID="ddlTerminal" runat="server" DataTextField="TRM_MNMC" DataValueField="TRM_ID">
</asp:DropDownList>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="lblTerminal" runat="server" Text='<%# Eval("TRM_MNMC") %>'></asp:Label>
</ItemTemplate>
<FooterTemplate>
<asp:DropDownList ID="ddlNewTerminal" runat="server" DataTextField="TRM_MNMC" DataValueField="TRM_ID">
</asp:DropDownList>
</FooterTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="TAS No" HeaderStyle-HorizontalAlign="Left">
<EditItemTemplate>
<asp:TextBox ID="txtTASNo" runat="server" Text='<%# Bind("TAS_NO") %>' Width="120"></asp:TextBox>
</EditItemTemplate>
<FooterTemplate>
<asp:TextBox ID="txtNewTASNo" runat="server" Width="120"></asp:TextBox>
</FooterTemplate>
<ItemTemplate>
<asp:Label ID="lblTASNo" runat="server" Text='<%# Bind("TAS_NO") %>' Width="120"></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="" ShowHeader="False">
<EditItemTemplate>
<asp:LinkButton ID="lbkUpdate" runat="server" CausesValidation="True" CommandName="Update" Text="Kaydet"></asp:LinkButton>
<asp:LinkButton ID="lnkCancel" runat="server" CausesValidation="False" CommandName="Cancel" Text="Cancel"></asp:LinkButton>
</EditItemTemplate>
<FooterTemplate>
<asp:LinkButton ID="lnkAdd" runat="server" CausesValidation="False" CommandName="Insert" Text="Insert"></asp:LinkButton>
</FooterTemplate>
<ItemTemplate>
<asp:LinkButton ID="lnkEdit" runat="server" CausesValidation="False" CommandName="Edit" Text="Edit"></asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
<asp:CommandField HeaderText="" ShowDeleteButton="True" ShowHeader="True" DeleteText="Delete"/>
</Columns>
</asp:GridView>
C#
// I am storing the data in ViewState
DataTable dtTerminals
{
get
{
return ViewState["_dtVehicleTerminals"] as DataTable;
}
set
{
ViewState["_dtVehicleTerminals"] = value;
}
}
//Page Load
protected void Page_Load(object sender, EventArgs e)
{
if (dtTerminals == null)
{
dtTerminals = new DataTable();
dtTerminals.Columns.Add("TRM_ID");
dtTerminals.Columns.Add("TRM_MNMC");
dtTerminals.Columns.Add("TAS_NO");
}
if (!IsPostBack)
{
string VhcId = Request["vhc_id"];//Edit mode
if (!string.IsNullOrEmpty(VhcId))
{
BindTerminalInfo(VhcId);
}
else
{
//To show empty grid
BindTerminalGrid();
}
}
// Bind Terminal Info
void BindTerminalInfo(string VhcId)
{
dtTerminals = VehicleManager.GetVehicleTerminals(VhcId);
BindTerminalGrid();
}
//Bind Terminal Grid
public void BindTerminalGrid()
{
if (dtTerminals.Rows.Count > 0)
{
grdTerminals.DataSource = dtTerminals;
grdTerminals.DataBind();
}
else
{
//Show No Records Found
dtTerminals.Rows.Add(dtTerminals.NewRow());
grdTerminals.DataSource = dtTerminals;
grdTerminals.DataBind();
grdTerminals.Rows[0].Cells.Clear();
grdTerminals.Rows[0].Cells.Add(new TableCell());
grdTerminals.Rows[0].Cells[0].Text = "No Data found";
dtTerminals.Rows.Clear();
}
}
//Other methods related to grid functionality
protected void grdTerminals_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
DropDownList ddlTerminal = (DropDownList)e.Row.FindControl("ddlTerminal");
if (ddlTerminal != null)
{
ddlTerminal.DataSource = VehicleManager.GetDefaultUserTerminalNames();
ddlTerminal.DataBind();
ddlTerminal.DataTextField = "TRM_MNMC";
ddlTerminal.DataValueField = "TRM_ID";
ddlTerminal.SelectedValue = grdTerminals.DataKeys[e.Row.RowIndex].Values[0].ToString();
}
}
if (e.Row.RowType == DataControlRowType.Footer)
{
DropDownList ddlNewTerminal = (DropDownList)e.Row.FindControl("ddlNewTerminal");
ddlNewTerminal.DataSource = VehicleManager.GetDefaultUserTerminalNames();
ddlNewTerminal.DataBind();
}
}
protected void grdTerminals_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
{
grdTerminals.EditIndex = -1;
BindTerminalGrid();
}
protected void grdTerminals_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
Label lblId = (Label)grdTerminals.Rows[e.RowIndex].FindControl("lblTrmUnqId");
DropDownList ddlTerminal = (DropDownList)grdTerminals.Rows[e.RowIndex].FindControl("ddlTerminal");
TextBox txtTASNo = (TextBox)grdTerminals.Rows[e.RowIndex].FindControl("txtTASNo");
dtTerminals.Rows[e.RowIndex]["TRM_ID"] = ddlTerminal.SelectedValue;
dtTerminals.Rows[e.RowIndex]["TRM_MNMC"] = ddlTerminal.SelectedItem;
dtTerminals.Rows[e.RowIndex]["TAS_NO"] = txtTASNo.Text;
grdTerminals.EditIndex = -1;
BindTerminalGrid();
}
protected void grdTerminals_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
string TrmId = Convert.ToString(grdTerminals.DataKeys[e.RowIndex].Values[0]);
dtTerminals.Rows.Remove(dtTerminals.Rows[e.RowIndex]);
BindTerminalGrid();
}
protected void grdTerminals_RowCommand(object sender, GridViewCommandEventArgs e)
{
if (e.CommandName.Equals("Insert"))
{
DropDownList ddlNewTerminal = (DropDownList)grdTerminals.FooterRow.FindControl("ddlNewTerminal");
TextBox txtTASNo = (TextBox)grdTerminals.FooterRow.FindControl("txtNewTASNo");
DataRow dr = dtTerminals.NewRow();
dr["TRM_ID"] = ddlNewTerminal.SelectedValue;
dr["TRM_MNMC"] = ddlNewTerminal.SelectedItem.Text;
dr["TAS_NO"] = txtTASNo.Text;
dtTerminals.Rows.Add(dr);
BindTerminalGrid();
}
}
protected void grdTerminals_RowEditing(object sender, GridViewEditEventArgs e)
{
grdTerminals.EditIndex = e.NewEditIndex;
BindTerminalGrid();
}

Answer 1

I am not sure it is the correct solution . But try adding Empty data text property of Gridview.
<asp:gridview id="CustomersGridView"
datasourceid="CustomersSqlDataSource"
autogeneratecolumns="true"
emptydatatext="No data in the data source."
runat="server">
<emptydatarowstyle backcolor="LightBlue"
forecolor="Red"/>
</asp:gridview>
Or try like this
<asp:TemplateField>
<EditItemTemplate>
<asp:ImageButton ID="imgBtnUpdate" runat="server" Height="32px"
ImageUrl="~/Images/Update.jpg" ToolTip="Update" Width="32px" CommandName="Update"/>
<asp:ImageButton ID="imgBtnDelete" runat="server" Height="32px"
ImageUrl="~/Images/delete.gif" style="margin-left: 0px" ToolTip="Delete"
Width="32px" CommandName="Delete"/>
<asp:ImageButton ID="imgBtnCancel" runat="server" Height="32px"
ImageUrl="~/Images/Cancel.png" ToolTip="Cancel" Width="32px" CommandName="Cancel"/>
</EditItemTemplate>
<FooterTemplate>
<asp:ImageButton ID="btnAdd" runat="server" ImageUrl="~/Images/AddNew.gif"
ToolTip="Add New Record" CommandName="Add"/>
</FooterTemplate>
<ItemTemplate>
<asp:ImageButton ID="imgBtnEdit" runat="server" Height="32px"
ImageUrl="~/Images/pencil.png" ToolTip="Edit" Width="32px" CommandName="Edit"/>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Name">
<EditItemTemplate>
<asp:TextBox ID="txtName" runat="server" Text='<%# Eval("name") %>'></asp:TextBox>
</EditItemTemplate>
<FooterTemplate>
<asp:TextBox ID="txtNameFooter" runat="server"></asp:TextBox>
</FooterTemplate>
<ItemTemplate>
<asp:Label ID="lblName" runat="server" Text='<%# Eval("name") %>'></asp:Label>
</ItemTemplate>

Answer 2

Finally I have fixed this problem. The solution is adding
if (!Request.Form["__EVENTTARGET"].Split('$').Contains(grdTerminals.ID))
{
BindTerminalGrid();
}
code block to If(Postback) statement. I should rebind data for everypostback but only if the control which caused postback is not the "datagrid".