Help with drawing a string

I have a problem hopefully someone can help me out with. I am trying to draw a string in a rectange (not inheriting from any control). The rectangle can only be so big. I need to figure out if the string will not fit in the rectangle, then add a "..." to the end of the string right before it gets cut off.
I know how to the draw the string, and I can figure out how measure it with the font and string formating. But finding that cut-off point is where I am having much difficulty.

Thanks!

There is a Graphics.MeasureString method you can use to measure the length of the string...

Like this?

VB Code:

Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint
        Dim txt As String
        Dim the_Font As New Font("Times New Roman", 30, FontStyle.Bold, GraphicsUnit.Pixel)
        Dim layout_rect As RectangleF
        Dim string_format As New StringFormat
 
        e.Graphics.TextRenderingHint = System.Drawing.Text.TextRenderingHint.ClearTypeGridFit
        layout_rect = New RectangleF(100, 0, 180, 70)
        txt = "Hello this is the text that is going to be trimmed"
        string_format.Trimming = StringTrimming.EllipsisCharacter
        e.Graphics.DrawString(txt, the_Font, Brushes.Black, layout_rect, string_format)
        e.Graphics.DrawRectangle(Pens.Red, Rectangle.Round(layout_rect))
 
    End Sub

I can already get the length of the string. What I need to find is the length of the "fitting" string and cut it off at the proper length. For example, a string that measures an area of 200,400. However the actually area displayed is 200, 200. I need to find that point in the string and add a "..." to indicate there is more text.

Thanks moeur!