how do I refresh gridview after adding new row? - vb.net

Question

I made several research but cannot figure out the problem. I can add, remove or edit rows from database in the code. However, I could not refresh the grid.
I mean, when I add new row to gridview, it doesn't appear in it. After I recompile the code it appears. How can I refresh the gridview?
Dim strSQL = "SELECT * FROM FIXEDCARD WHERE STKCODE = '" & TextEdit1.Text & "'"
objCon.Close()
Dim sqlCmd As New SqlCommand(strSQL, objCon)
objCon.Open()
Dim dreader As SqlDataReader
dreader = sqlCmd.ExecuteReader
If dreader.Read Then
'Dim stk_ As String = dreader.GetString(dreader.GetOrdinal("STKCODE")).ToString()
DevExpress.XtraEditors.XtraMessageBox.Show("already exists", "Info!", MessageBoxButtons.OK)
objCon.Close()
Else
dreader.Close()
strSQL = "INSERT INTO FIXEDCARD(STKCODE, STKEXP, AUTHCODE, GRPCODE, SPECODE" & _
", SPECODE2, SPECODE3, SPECODE4, SPECODE5, AMORTRATIO, AMORT," & _
"PURCH, SALES, RETUR, UNIT) VALUES('" & TextEdit1.Text & "'," & _
"'" & TextEdit2.Text & "', '" & TextEdit3.Text & "'," & _
"'" & TextEdit4.Text & "', '" & TextEdit5.Text & "'," & _
"'" & TextEdit6.Text & "', '" & TextEdit7.Text & "'," & _
"'" & TextEdit8.Text & "', '" & TextEdit9.Text & "'," & _
"'" & TextEdit10.Text & "', '" & TextEdit11.Text & "'," & _
"'" & TextEdit12.Text & "', '" & TextEdit13.Text & "'," & _
"'" & TextEdit14.Text & "', '" & TextEdit15.Text & "') "
sqlCmd = New SqlCommand(strSQL, objCon)
sqlCmd.ExecuteNonQuery()
objCon.Close()
End If
RefreshGrid()
Me.Close()
And also I try to write a refresh function that will refresh the gridview when I call it each button. However, I have been making a mistake but could not recognize it.
Public Sub RefreshGrid()
Dim T As New DataTable
Dim strSQL = "Select * From FIXEDCARD"
Dim sqlCmd As New SqlCommand(strSQL, objCon)
T = CType(sqlCmd.ExecuteNonQuery(), System.Data.DataTable)
GridView1.DataSource = T
End Sub

Answer 1

Public Function FillDataSet(query As String, ByVal ParamArray para() As Object) As DataTable
dim _transaction As SqlTransaction
Dim _command As SqlCommand
_command = New SqlCommand(query, yourConnection)
_ds = New DataSet
_sqlda = New SqlDataAdapter(_command )
_command.Transaction = _transaction
For i = 0 To para.Count - 1
_command.Parameters.AddWithValue("#" & i, para(i))
Next
_sqlda.Fill(_ds)
return _ds.tables(0)
End Function
call it
GridControl1.datasource = Nothing
GridControl1.datasource = FillDataSet(YourInsertQuery,YourParam)
GridControl1.RefreshDataSource()

Answer 2

You are using a "Non-Query" in the refresh. This doesn't return a table value.
Try using the SqlCommand.ExecuteReader method.
Reference: https://msdn.microsoft.com/en-us/library/9kcbe65k(v=vs.110).aspx