默认情况下，除非您通过调用以下命令将TextBox注册为自绘制控件，否则不会在TextBox上调用OnPaint：

SetStyle(ControlStyles.UserPaint, true);

例如，从MyTextBox构造函数。

您需要切换OnPaint中的呼叫

protected override void OnPaint(PaintEventArgs e)
{
    base.OnPaint(e);
    ControlPaint.DrawBorder(e.Graphics, this.Bounds, Color.Red, ButtonBorderStyle.Solid);
}

base.OnPaint()像往常一样绘制TextBox。如果在base调用之前调用DrawBorder *，则它将再次被基本实现覆盖。
但根据documentation，TextBox不支持Paint事件：
此API支持产品基础结构，不打算直接从代码中使用。
在重绘控件时发生。此事件与此类无关。
所以本·杰肯的答案应该能解决这个问题。

我所做的是在窗口收到WM_PAINT消息后创建图形对象。

**C#

protected override void WndProc(ref Message m)
{
    base.WndProc(m);
    switch (m.Msg)
    {
        case WM_PAINT:
            BackgroundText();
            break;
    }
}

private void BackgroundText()
{
    if (DesignMode)
    {
        using (Graphics G = CreateGraphics())
        {
            TextRenderer.DrawText(G, "Project No.", new Font("Microsoft Sans Serif", 8.25), new Point(3, 1), Color.FromArgb(94, 101, 117));
        }
        return;
    }
    if (string.IsNullOrEmpty(Text))
    {
        using (Graphics G = CreateGraphics())
        {
            Color tColor = FindForm.ActiveControl == this ? Color.FromArgb(94, 101, 117) : SystemColors.Window;
            TextRenderer.DrawText(G, "Project No.", new Font("Microsoft Sans Serif", 8.25), new Point(3, 1), tColor);
        }
    }
}

*VB.NET

Protected Overrides Sub WndProc(ByRef m As Message)
    MyBase.WndProc(m)
    Select Case m.Msg
        Case WM_PAINT
            BackgroundText()
    End Select
End Sub

Private Sub BackgroundText()
    If DesignMode Then
        Using G As Graphics = CreateGraphics()
            TextRenderer.DrawText(G, "Project No.", New Font("Microsoft Sans Serif", 8.25), New Point(3, 1), Color.FromArgb(94, 101, 117))
        End Using
        Return
    End If
    If String.IsNullOrEmpty(Text) Then
        Using G As Graphics = CreateGraphics()
            Dim tColor As Color = If(FindForm.ActiveControl Is Me, Color.FromArgb(94, 101, 117), SystemColors.Window)
            TextRenderer.DrawText(G, "Project No.", New Font("Microsoft Sans Serif", 8.25), New Point(3, 1), tColor)
        End Using
    End If
End Sub