Styjun

As far as I was told and as I read about it, the ComboBox with the property DropDownStyle set to DropDownList is a combination of:

A TextBox that doesn't show a cursor and only shows items when the user presses UP, DOWN, or keys equivalent to the items on the list. E.g., if there's an item named INPUT and an item named OUTPUT on the DropDownList, by pressing the key I the ComboBox would show INPUT, while pressing the key O would show OUTPUT;

A Button that shows the DropDownList;

A DropDownList, which only drops when the user presses the Button.

Assuming the above is correct, let me mention what I've tried so far. I've searched ways of manipulating the three elements I mentioned above and found some answers, unfortunately most of them were related to ASP.NET and C#.NET.

I've successfully set the BackColor and ForeColor of both default and selected state of the items on the DropDownList.

I've tried drawing a Rectangle over the border of the element TextBox and the element DropDownList of this ComboBox, but these rectangles stay beneath the actual borders.

Private Sub cmbType_DrawItem(ByVal sender As Object, ByVal e As System.Windows.Forms.DrawItemEventArgs) Handles cmbType.DrawItem

 Dim itemBackColorDefault As Brush, itemForeColorDefault As Brush
 Dim itemBackColorSelected As Brush, itemForeColorSelected As Brush

 itemBackColorDefault = Brushes.DarkGray
 itemForeColorDefault = Brushes.WhiteSmoke
 itemBackColorSelected = Brushes.WhiteSmoke
 itemForeColorSelected = Brushes.DarkGray

 Dim myPen As Pen
 Dim myGraphics As Graphics = Me.CreateGraphics

 myPen = New Pen(Drawing.Color.Red, 1)
 myGraphics.DrawRectangle(myPen, 133, 25, 130, 20) 'Supposed to draw a red rectangle above the border of the element TextBox of cmbType, but it stays beneath it
 e.Graphics.DrawRectangle(myPen, -1, -1, 130, 31) 'Supposed to draw a red rectangle above the border of the element DropDownList of cmbType when the element Button of cmbType is clicked, but, again, it stays beneath it

 If e.Index < 0 Then Exit Sub

 Dim rct As Rectangle = e.Bounds
 Dim itemText As String = cmbType.Items(e.Index)

 If e.State And DrawItemState.Selected Then

 'Selected BackColor
 e.Graphics.FillRectangle(itemBackColorSelected, rct)

 'Selected ForeColor
 e.Graphics.DrawString(itemText, Me.cmbType.Font, itemForeColorSelected, rct.X, rct.Y)

 Else

 'Default BackColor
 e.Graphics.FillRectangle(itemBackColorDefault, rct)

 'Default ForeColor
 e.Graphics.DrawString(itemText, Me.cmbType.Font, itemForeColorDefault, rct.X, rct.Y)

 End If

End Sub

The expected result and actual result can be summarized in one image:

LEFT is the actual result, RIGHT is the expected result.

To be more specific, what I want to change is as follow.

TextBox: border color;

Button: border color and BackColor, arrow color and shape;

DropDownList: border color (both default state and selected state).