Hello,
I am currently trying to sort on a GridView after it has been populated with records from a SQL Server Express database.
I click on a column to sort it and I get the following error:
"DataTable must be set prior to using DataView."
The entirety of my code is as follows:
<script runat="server" >
Protected Sub Button3_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button3.Click
Dim sqlConn As New SqlConnection
Dim sqlCmd As New SqlClient.SqlCommand
Dim sqlReader As SqlDataReader
'If no values are supplied in the textbox, throw an error message.
If TextBox2.Text = "" Then
MsgBox("A centre code needs to be provided...")
End If
If TextBox2.Text <> "" Then
'Telling the system the location of the database.
sqlConn.ConnectionString = "server=ServerName;Initial Catalog=dbName;Trusted_Connection=yes"
'Here we are opening the connection to the database.
sqlConn.Open()
'This is to say that sqlCmd is a stored procedure.
sqlCmd.CommandType = System.Data.CommandType.StoredProcedure
'This is creating the command to execute the stored procedure based on the information given in the connection string.
sqlCmd = sqlConn.CreateCommand
'The command is triggered to execute the stored procedure which grabs all information for the specific centre.
sqlCmd.CommandText = "exec ProcedureName'" & TextBox2.Text & "' "
'This will read the rows in the database.
sqlReader = sqlCmd.ExecuteReader()
'If there are rows of data that match are criteria
If (sqlReader.HasRows) Then
'The rows of data are grabbed for the specific centre from the database using the data reader.
GridView2.DataSource = sqlReader
GridView2.DataBind()
Else
MsgBox("The centre code provided does not exist...")
End If
'This is closing the connection to the database once we have finished with it.
sqlConn.Close()
'This is to clear the list of items out of the GridView box.
End If
End Sub
Protected Sub gvSorting_Sorting(ByVal sender As Object, ByVal e As GridViewSortEventArgs)
Dim dtSortView As New DataTable
dtSortView = GridView2.DataSource
If dtSortView Is Nothing Then
Dim dvSortedView As New DataView(dtSortView)
dvSortedView.Sort = e.SortExpression + " " + getSortDirectionString(e.SortDirection)
GridView2.DataSource = dvSortedView
GridView2.DataBind()
End If
End Sub
Public Function getSortDirectionString(ByVal SortDirection As SortDirection) As String
Dim newSortDirection As String = String.Empty
If (SortDirection = SortDirection.Ascending) Then
newSortDirection = "ASC"
Else
newSortDirection = "DESC"
'Return newSortDirection
End If
Return newSortDirection
End Function
</script>My error comes on the following code line:
dvSortedView.Sort = e.SortExpression + " " + getSortDirectionString(e.SortDirection)If anybody can give me any hints and tips on why this is happening, I would be extremely grateful.
From my understanding its telling me that there is no records in the GridView to sort, but why?
Thanks in advance,
Dan
