Expression column in datagridview

[rony01]

Hi friends
I am new to using datagridview ,I am trying to learn how to add an expression column in datagridview .can someone tell me why the total column gives me wrong out put ?

 Dim dt As New DataTable
        dt.Columns.Add("col1")
        dt.Columns.Add("col2")
        dt.Columns.Add("col3")
        dt.Columns.Add("col4")
        dt.Columns.Add("total")

        dt.Rows.Add("")
        dt.Rows.Add("")
        dt.Rows.Add("")
        dt.Rows.Add("")

        Me.DataGridView1.DataSource = dt
        dt.Columns("total").Expression = "[col2]+[col3]"

 

[garths2]

Since it has been a while since you posted this question I don't know if you already figured it out. I ran your code as is and it concatenated the column values; I am guessing that is the same issue you had.

Just change the data type of the columns right after you add them to the data table then it will work.

dt.Columns.Add("col1")
dt.Columns.Add("col2")
dt.Columns.Add("col3")
dt.Columns.Add("col4")
dt.Columns.Add("total")

dt.Columns.Add("col2", System.Type.GetType("System.Double"))
dt.Columns.Add("col3", System.Type.GetType("System.Double"))
dt.Columns.Add("total", System.Type.GetType("System.Double"))