更新数据绑定的DataGridView

Question

I have a DataGridView that is databound to a dataset. However I am trying to run a Query no the datasource and update the DataGridView to display the Query Results.

The code I'm using is:

 Public Sub Call_Filter()

        Dim myCon = New OleDbConnection(My.Settings.Database_string)

        Try
            myCon.Open()
        Catch ex As Exception
            MsgBox("Sorry, An Error Occurred" & vbNewLine & _
                   "Database Not Found!" & vbNewLine & vbNewLine & _
                   "Error Message: " & ex.Message, MsgBoxStyle.OkOnly, "Could Not Locate Database")
            Main.VIEW_SavingMessage.Visible = False
            Exit Sub
        End Try

        Dim FilterAdaptor = New OleDbDataAdapter

        Dim FilterAdaptorText = "SELECT ID, [Name Of Person], [SAP Job Number], [Site Name], [Asset Description], [Spares Supplier], [Supplier Contact Name], [Supplier Contact Phone Number], " & _
                                  "[Supplier Contact Email], [Spares Description], [Part Number], [Quantity To Order], Cost, Comments, [Request Date], [Date Ordered], [Ordered By], [Invoice Received], " & _
                                  "[Invoice Paid], [Method Of Payment], [Date Item Received], [Quote Attatchment], [Marked As Urgent] " & _
         "FROM Spares " & _
         "WHERE ([Name Of Person] = @NameOfPerson OR @NameOfPerson = '' OR @NameOfPerson IS NULL) AND " & _
         "([SAP Job Number] = @SAPJobNo OR @SAPJobNo = '' OR @SAPJobNo IS NULL)"

        Dim FilteredDataSet = New DataSet

        Dim sqr As OleDbCommand = New OleDbCommand(FilterAdaptorText, myCon)

        sqr.Parameters.Add("@NameOfPerson", OleDbType.VarChar).Value = Main.Name_Of_PersonToolStripTextBox.Text
        If Main.FilterJobNo.Text <> "" Then
            sqr.Parameters.Add("@SAPJobNo", OleDbType.Integer).Value = Main.FilterJobNo.Text
        Else
            sqr.Parameters.Add("@SAPJobNo", OleDbType.Integer).Value = DBNull.Value
        End If

        Try
            sqr.ExecuteNonQuery()

        Catch ex As Exception
            MsgBox("Sorry, An error occured!" & vbNewLine & _
       "The database rejected the request" & vbNewLine & vbNewLine & _
       "Error Message: " & ex.Message, MsgBoxStyle.OkOnly, "Database Refused Query")
            Exit Sub
        End Try

        FilterAdaptor.SelectCommand = sqr
        FilterAdaptor.Fill(FilteredDataSet)
        Main.DataGridView1.DataSource = FilteredDataSet

        myCon.Close()

    End Sub

Whilst this code executes corretly, and throws no errors, it returns a blank row to the DataGridView , not the correct filtered results. I know the filter query works correctly as I have tested it through Access and it returns the correct inormation.

I Can't use any other method that this as I have a large query to execute, this is just a fraction of the filter query for testing.

It appears that the issue I'm having is trying to get the filtered information in to my DataGridView . Am I missing something basic? I've managed to insert, read and delete from databases in a similar method, but this doesn't seem to work when using a WHERE command.

UPDATE - 29/06/15

I'm still trying to get this to work, but after researching have changed my approach to this:

 Public Function getDataSet() As DataSet
        Dim ds As New Data.DataSet
        ds.Tables.Add(New DataTable("Filtered"))


        Dim Con As New OleDb.OleDbConnection(My.Settings.Database_string)
        Con.Open()
        Dim ad As New Data.OleDb.OleDbDataAdapter("SELECT ID, [Name Of Person] " & _
     "FROM Spares " & _
     "WHERE [Name Of Person] = Joe", Con)

        ad.Fill(ds.Tables("Filtered"))

        Return ds
    End Function

Whats happening now is that I'm getting the following error:

No value given for one or more required parameters.

But I don't understand where this supposed "Parameter" has come from? I haven't used any parameters?

Thanks

Answer 1

There WHERE clause of your query is wrong.

"WHERE ([Name Of Person] = @NameOfPerson OR @NameOfPerson = '' OR @NameOfPerson IS NULL) AND 

Since the parameter/variable is just one condition for [Name of Person] . it should only appear once in the WHERE. If the name of the person is "Bob", that portion would resolve to:

"WHERE ([Name Of Person] = 'Bob' OR 'Bob'= '' OR 'Bob' IS NULL) AND ...

Clearly, "Bob" is never going to be Null or '' . Those should all be the column name:

"WHERE ([Name Of Person] = 'Bob' OR [Name Of Person]= '' OR [Name Of Person] IS NULL) AND ...

The same would be true for the [SAP Job Number] portion.

Answer 2

You don't seem to be binding your data. Try DataGridView1.Databind() after you set the Datasource.

Answer 3

I finally managed to get it going using this:

Public Function getDataSet() As DataSet
        Dim ds As New Data.DataSet
        ds.Tables.Add(New DataTable("Filtered"))


        Dim Con As New OleDb.OleDbConnection(My.Settings.Database_string)
        Con.Open()
        Dim ad As New Data.OleDb.OleDbDataAdapter




        Dim cmd As New OleDbCommand("SELECT * FROM Spares " & _
                                    "WHERE ([Name Of Person] = @NOP OR [Name Of Person] = '' OR [Name Of Person] IS NULL Or @NOP IS NULL) AND " & _
                                    "([SAP Job Number] = @SJN OR [SAP Job Number] = '' OR [SAP Job Number] IS NULL Or @SJN IS NULL)", Con)

        If Main.Name_Of_PersonToolStripTextBox.Text = "" Then
            cmd.Parameters.AddWithValue("@NOP", DBNull.Value)
        Else
            cmd.Parameters.AddWithValue("@NOP", Main.Name_Of_PersonToolStripTextBox.Text)
        End If

        If Main.FilterJobNo.Text = "" Then
            cmd.Parameters.AddWithValue("@SJN", DBNull.Value)
        Else
            cmd.Parameters.AddWithValue("@SJN", Main.FilterJobNo.Text)
        End If

        ad.SelectCommand = cmd
        ad.Fill(ds.Tables("Filtered"))


        Return ds
    End Function

and calling it using this:

Private Sub FILTER_Accept_Button_Click(sender As Object, e As EventArgs) Handles FILTER_Accept_Button.Click
        DataGridView1.DataSource = Database_Management_Codes.getDataSet().Tables(0)
    End Sub