How To Update A Column In A DataGrid Using C#.NET? I am getting InvalidCastEx

How To Update A Column In A DataGrid Using C#.NET?

I am getting InvalidCastException as (Specified cast is not
valid) while updating 2nd column in a datagrid?
Id,firstname,lastname are the three columns of my datagrid
respectively. I wanted to edit the second column(lastname)
and update it. I did the following code in DataGrid's
updatecommand(),but failed to update !

Int varid=(int)DataGrid1.DataKeys[e.Item.ItemIndex];
TextBox lnm=(TextBox)e.Item.Cells[2].Controls[0]; string
str=lnm.Text ; SqlCommand cmd=new SqlCommand("update
customer set lastname='" + str + "' where id=" + varid
+ "",con); cmd.ExecuteNonQuery(); DataGrid1.EditItemIndex=-
1; DataGrid1.DataBind();

Question Posted / pen2satya

2 Answers
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How To Update A Column In A DataGrid Using C#.NET? I am getting InvalidCastException as (Specifie..

Answer / aravazhi

Try this query you can avoid InvalidCastException...

string strQry = "update customer set lastname=@LastName
where id=@VarId";
SqlCommand cmd=new SqlCommand(strQry,con);
int varid = (int)DataGrid1.DataKeys[(int)e.Item.ItemIndex];
string LName = ((TextBox)e.Item.FondControl
("txtLName")).Text;//txtLname is ID of control
cmd.Paramters.Add(new SqlParameter("@LastName",LName));
cmd.Paramters.Add(new SqlParameter("@VarId",varid));
cmd.ExecuteNonQuery();
DataGrid1.EditItemIndex=- 1;
DataGrid1.DataBind();

Is This Answer Correct ?

15 Yes

4 No

How To Update A Column In A DataGrid Using C#.NET? I am getting InvalidCastException as (Specifie..

Answer / pk

public void DataGrid1_Update(Object sender,
DataGridCommandEventArgs e)
{

string unitprice =
((TextBox)e.Item.Cells[3].Controls[0]).Text;

string quantity =
((TextBox)e.Item.Cells[4].Controls[0]).Text;

string discount =
((TextBox)e.Item.Cells[5].Controls[0]).Text;

int orderid =
(int)DataGrid1.DataKeys[(int)e.Item.ItemIndex];

string productid =
((TextBox)e.Item.Cells[2].Controls[0]).Text;

try
{

string updateCmd = "UPDATE [Order Details] SET
UnitPrice = @UnitPrice,"

+ "Quantity = @Quantity, Discount = @Discount
where OrderId =@OrderId and ProductId=@ProductId";

SqlConnection cn = new SqlConnection(strConn);

SqlCommand myCommand = new SqlCommand(updateCmd,
cn);

myCommand.Parameters.Add(new
SqlParameter("@UnitPrice", Convert.ToDecimal(unitprice)));

myCommand.Parameters.Add(new
SqlParameter("@Quantity", Convert.ToInt16(quantity)));

myCommand.Parameters.Add(new
SqlParameter("@Discount", Convert.ToInt16(discount)));

myCommand.Parameters.Add(new
SqlParameter("@OrderId", orderid));

myCommand.Parameters.Add(new
SqlParameter("@ProductId", Convert.ToInt16(productid)));

cn.Open();

myCommand.ExecuteNonQuery();

DataGrid1.EditItemIndex = -1;

BindGrid();

}

catch (Exception ex)
{

lblError.Visible = true;

lblError.Text = (ex.Message);

}