Datagrid + Generic List + Hide Columns

Hi all,

I have the following situation:

A WM5/PPC application with a datagrid that have a generic list of object as datasource. The list of Object is actually a List(of Product) where Product class is a value object with some classic properties, prduct id, code, name etc...

I want to hide some of the fields being displayed and attempted to do so by hiding datagrid columns using DataGridTableStyle. I converted some code from C# and tried to use:


dim ts as new DataGridTableStyle
ts.GridColumnStyles.AddColumn(...)


But it would seem that AddColumn is not a member of GridColumnStyles and it only has the Add method which takes a DataGridColumnStyle as parameter. So i'm a bit :confused: here, is there any way to achieve this hiding of columns?

Set their widths to 0

But I am unable to declare an object as DataGridColumnStyle... This class does not seem to be available, also as mentionned in my first post, GridColumnStyles does not have AddColumn as a member but Add only...

Use System.Windows.Forms.DataGridColumnStyle

Dim locationCol1 As New DataGridTextBoxColumn
Dim locationCol2 As New DataGridTextBoxColumn
.....
Dim aGridTableStyle2 As New DataGridTableStyle
aGridTableStyle2.MappingName = "Source"
.....
With locationCol1
.MappingName = "Reg No"
.Width = 70
.NullText = ""
End With

With locationCol2
.MappingName = "Status"
.Width = 0
.NullText = ""
End With
....
With aGridTableStyle2.GridColumnStyles
.Add(locationCol1)
.Add(locationCol2)
End With

....
dgPermits.TableStyles.Add(aGridTableStyle2)

Should help

Hmm actually i found that using width=-1 actually hide the column, width=0 didn't do it right.

Does not seem to work, on thing I forgot to mention is that I have a generic List(Of Object) as datasource. Each object is in fact a simple Product Class object. From the code you pasted petevick the compiler does not complain, but then i cannot see the column header text as per your code. Any ideas?

Code as below:

Code:

---

            Cursor.Current = Cursors.WaitCursor
            Dim objList As List(Of Object) = objProductBO.GetProduct()
            Cursor.Current = Cursors.Default

            Dim locationCol1 As New DataGridTextBoxColumn
            Dim locationCol2 As New DataGridTextBoxColumn

            Dim aGridTableStyle2 As New DataGridTableStyle
            aGridTableStyle2.MappingName = "Source"

            With locationCol1
                .MappingName = "Reg No"
                .Width = 70
                .NullText = ""
            End With

            With locationCol2
                .MappingName = "Status"
                .Width = 0
                .NullText = ""
            End With

            With aGridTableStyle2.GridColumnStyles
                .Add(locationCol1)
                .Add(locationCol2)
            End With

            dtgProduct.TableStyles.Clear()
            dtgProduct.TableStyles.Add(aGridTableStyle2)

            If Not objList Is Nothing Then
                dtgProduct.DataSource = objList
            End If

---

Whether I assign the datasource before or after the column formating code does not make any difference

Hi,
I seem to remember that code doesn't show headings on the grid. Take a look at the 'headertext' property (I think :))

Still does not work... Could it be that the DataGridTextBoxColumn object is unable to map property name of an object with the MappingName when a List of Object is bound to a datagrid?

Here's a sample code I am trying to test:

Employee Class:

Code:

---

Public Class Employee

    Private empId As Integer
    Public Property EmployeeId() As Integer
        Get
            Return empId
        End Get
        Set(ByVal value As Integer)
            empId = value
        End Set
    End Property


    Private empCode As String
    Public Property EmployeeCode() As String
        Get
            Return empCode
        End Get
        Set(ByVal value As String)
            empCode = value
        End Set
    End Property

    Private empName As String
    Public Property EmployeeName() As String
        Get
            Return empName
        End Get
        Set(ByVal value As String)
            empName = value
        End Set
    End Property

End Class

---

Form Code:

Code:

---

    Private empList As New List(Of Employee)

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        Dim locationCol1 As New DataGridTextBoxColumn
        Dim locationCol2 As New DataGridTextBoxColumn

        Dim aGridTableStyle2 As New DataGridTableStyle
        aGridTableStyle2.MappingName = "Source"

        With locationCol1
            .MappingName = "EmployeeId"
            .Width = -1
            .NullText = ""
        End With

        With aGridTableStyle2.GridColumnStyles
            .Add(locationCol1)
        End With

        For index As Integer = 1 To 10
            Dim emp As New Employee
            With emp
                .EmployeeId = index
                .EmployeeCode = String.Concat("EM", index.ToString)
                .EmployeeName = String.Concat("Test Employee ", index.ToString)
            End With
            empList.Add(emp)
        Next

        DataGrid1.DataSource = empList
        DataGrid1.TableStyles.Clear()
        DataGrid1.TableStyles.Add(aGridTableStyle2)

    End Sub

---

I suspect that the property name is not the same as the Mapping Name. Any suggestions?

Couldn't test that code atm but could you try:
aGridTableStyle2.MappingName = empList.toString()

Here's the code i'm using for the same purpose as you...
Note that i have 2 custom classes called DataGridColoredTextBoxColumn and DataGridCustomTextBoxColumn, you might want to ignore that.

vb Code:

Private Sub formataGrelhaEntidades()
        Try
            Dim aGridTableStyle2 As New DataGridTableStyle
            Dim locationCol1 As New DataGridColoredTextBoxColumn
            Dim locationCol2 As New DataGridCustomTextBoxColumn
            Dim locationCol3 As New DataGridTextBoxColumn
            Dim locationCol4 As New DataGridTextBoxColumn
            Dim locationCol5 As New DataGridTextBoxColumn
 
            aGridTableStyle2.MappingName = myDataset.ToString
            Me.DataGridEntidades.RowHeadersVisible = False
            Me.DataGridEntidades.ColumnHeadersVisible = True
            With locationCol1
                .backgroundColor = Color.LightSteelBlue
                .ForeColor = Color.Black
                .MappingName = "Cod"
                .HeaderText = "Cod"
                .Width = 44
                .NullText = ""
            End With
            With locationCol2
                .Owner = Me.DataGridEntidades
                .Alignment = HorizontalAlignment.Left
                .AlternatingBackColor = Color.LightSteelBlue
                .MappingName = "Nome"
                .HeaderText = "Empresa"
                .ReadOnly = True
                .Width = Screen.PrimaryScreen.WorkingArea.Width - locationCol1.Width - 16
                .NullText = ""
            End With
            With locationCol3
                .MappingName = "Morada"
                .HeaderText = "Morada"
                .Width = -1
                .NullText = ""
            End With
            With locationCol4
                .MappingName = "CodPostal"
                .HeaderText = "CodPostal"
                .Width = -1
                .NullText = ""
            End With
            With locationCol5
                .MappingName = "Contacto"
                .HeaderText = "Contacto"
                .Width = -1
                .NullText = ""
            End With
 
            With aGridTableStyle2.GridColumnStyles
                .Add(locationCol1)
                .Add(locationCol2)
                .Add(locationCol3)
                .Add(locationCol4)
                .Add(locationCol5)
            End With
            With DataGridEntidades
                .BackColor = Color.AliceBlue
                .BackgroundColor = Color.AliceBlue
                .GridLineColor = Color.RoyalBlue
                .HeaderBackColor = Color.SteelBlue
                .SelectionBackColor = Color.LightCoral
                .SelectionForeColor = Color.DarkBlue
            End With
            DataGridEntidades.TableStyles.Clear()
            DataGridEntidades.TableStyles.Add(aGridTableStyle2)
        Catch ex As Exception
            '
        End Try
    End Sub

aGridTableStyle2.MappingName = empList.toString() does not do much... :(

Have you ever try to use datasets? They use to help, they are fast reading data too.