Change Caret Color in textbox - vb.net

Question

I use this code to create a caret in a textbox (vb.net):
Private Declare Function CreateCaret Lib "user32" (ByVal hwnd As Long, ByVal hBitmap As Long, ByVal nWidth As Long, ByVal nHeight As Long) As Long
Private Declare Function DestroyCaret Lib "user32" () As Long
Private Declare Function SetCaretBlinkTime Lib "user32" (ByVal wMSeconds As Long) As Long
Private Declare Function SetCaretPos Lib "user32" (ByVal x As Long, ByVal y As Long) As Long
Private Declare Function ShowCaret Lib "user32" (ByVal hwnd As Long) As Long
Private Declare Function HideCaret Lib "user32" (ByVal hwnd As Long) As Long
Private Sub txtOutput_GotFocus(sender As Object, e As EventArgs) Handles txtOutput.GotFocus
CreateCaret(txtOutput.Handle, IntPtr.Zero, 9, 12)
ShowCaret(txtOutput.Handle)
End Sub
Is it possible to change the color of the caret?

Answer 1

The problem you have is your PInvoke functions aren't declared properly. Look them up and match them with http://pinvoke.net/.
The calls to create the caret will take a bitmap handle. So depending on what your caret looks like, you just need to create a bitmap and pass it to the CreateCaret function to change it's color. Here's some (very) rough code I used to change the caret color of a regular textbox. Just note that I only changed CreateCaret and ShowCaret to the proper signatures from http://www.pinvoke.net. You will have to change the rest.
Public Class Form1
Private Declare Function CreateCaret Lib "user32" (ByVal hWnd As IntPtr, ByVal hBitmap As IntPtr, ByVal nWidth As Integer, ByVal nHeight As Integer) As Boolean
Private Declare Function DestroyCaret Lib "user32" () As Long
Private Declare Function SetCaretBlinkTime Lib "user32" (ByVal wMSeconds As Long) As Long
Private Declare Function SetCaretPos Lib "user32" (ByVal x As Long, ByVal y As Long) As Long
Private Declare Function ShowCaret Lib "user32" (ByVal hwnd As IntPtr) As Boolean
Private Declare Function HideCaret Lib "user32" (ByVal hwnd As Long) As Long
Private caretBitmap as Bitmap
Private Sub txtOutput_GotFocus(sender As Object, e As EventArgs) Handles txtOutput.GotFocus
If caretBitmap Is Nothing Then
caretBitmap = CreateCaretBitmap()
End If
CreateCaret(txtOutput.Handle, caretBitmap.GetHbitmap(), 5, 10)
ShowCaret(txtOutput.Handle)
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
End Sub
Private Function CreateCaretBitmap() As Bitmap
Dim flag As New Bitmap(5, 5)
Dim flagGraphics As Graphics = Graphics.FromImage(flag)
flagGraphics.FillRectangle(Brushes.Chartreuse, 0, 0, 5, 10)
Return flag
End Function
End Class
You can create the bitmap however you want obviously.
Hope that helps.