Auto-Resize Columns in a data grid

So the data grids I've been working with are inherited from System.Windows.Forms.DataGrid. The problem I had was when a user double clicks between a column on the header to auto-fit the width of the column based on the data. Inside the inherited control you need something like:

Protected Overloads Overrides Sub OnMouseDown(ByVal e As MouseEventArgs)
If e.Button = MouseButtons.Left And e.Clicks > 1 And (Me.HitTest(e.X, e.Y).Type = DataGrid.HitTestType.ColumnResize) Then
Return 'Prevent sorting on the column if it's a resize
End If
End Sub



Then in the form's double click event I put something like:

Dim CursorPosition As System.Drawing.Point = dgr.PointToClient(Cursor.Position)
Dim DataGridHitTestInfo As DataGrid.HitTestInfo = dgr.HitTest(CursorPosition)

If DataGridHitTestInfo.Type = DataGrid.HitTestType.ColumnResize Or DataGridHitTestInfo.Type = DataGrid.HitTestType.ColumnHeader Then
Application.DoEvents()

Select Case DataGridHitTestInfo.Column
Case 2
Me.col2.Width() = ResizeColumn(Me.col2.MappingName, Me.col2.HeaderText)
Case 3
Me.col3.Width() = ResizeColumn(Me.col3.MappingName, Me.col3.HeaderText)
Case 4
Me.col4.Width() = ResizeColumn(Me.col4.MappingName, Me.col4.HeaderText)
Case 5
Me.col5.Width() = ResizeColumn(Me.col5.MappingName, Me.col5.HeaderText)
Case 6
Me.col6.Width() = ResizeColumn(Me.col6.MappingName, Me.col6.HeaderText)
End Select

Column_WidthChanged(sender, e)
End If



And added a function like this:


Private Function ResizeColumn(ByVal columnName As String, ByVal header As String) As System.String
Dim i As Integer
Dim length As Single = 0
Dim g As System.Drawing.Graphics = Me.dgr.CreateGraphics
Dim str As System.String
Dim strLength As Single
length = System.Math.Max(g.MeasureString(header, Me.Font).Width(), length)
For i = 0 To Me.dsPCDCodes.Tables(0).Rows.Count - 1
If Not IsDBNull(Me.ds.Tables(0).Rows(i).Item(columnName)) Then
str = CType(Me.ds.Tables(0).Rows(i).Item(columnName), System.String)
strLength = g.MeasureString(str, Me.Font).Width()
length = System.Math.Max(strLength, length)
End If
Next
Return length
End Function

Auto width in a data grid to fit data

Intersting way to auto fit the column width in a data grid to fit the width of the data. You basically use the graphics for the data grid and use a function called MeasureString. Send in the string and the font that will be used, and get the width from this.

Dim i As Integer
Dim length As Integer = 0
Dim g As System.Drawing.Graphics = Me.dgr.CreateGraphics
Dim str As System.String
Dim strLength As Single

For i = 0 To ds.Tables(0).Rows.Count - 1
str = CType(ds.Tables(0).Rows(i).Item("Name"), System.String)
strLength = g.MeasureString(str, Me.Font).Width()
length = System.Math.Max(strLength, length)
Next

'Set Length
Me.col.Width = length