Sizing a label properly [Resolved]

[mendhak]

I'm trying to create a custom messagebox. The MessageBox's form obviously contains a label.

Just like the Windows MessageBox:
The text in the label could be of any length.
The label is of fixed width.
The label can have varying height.

The third point is the problem right now, I don't know how to make it have a varying height, I'd like to make it size itself accordingly with the text in there.


Here is what I tried:

Dim _tmp_Graphics As System.Drawing.Graphics
 
 
            Dim [hl=yellow]_tmp_SizeF As New System.Drawing.SizeF(_tmp_Graphics.MeasureString(_lbl.Text, _lbl.Font))[/hl]
 
            Dim _lblSize_Height As Single
            Dim _lblSize_Width As Single
 
            _lblSize_Height = _tmp_SizeF.Height
            _lblSize_Width = _tmp_SizeF.Width
 
            .Size = New System.Drawing.Size(_lblSize_Width, _lblSize_Height)

_lbl is a System.Windows.Forms.Label.

This errors out with a

NullReferenceException
Object reference not set to an instance of an object.

on the yellow, highlighted line above.

I can see that _tmp_Graphics = Nothing, but System.Drawing.Graphic's New() is private.

Really not sure if this is even the right approach.

Guidance, please.

[Cander]

Dim _tmp_Graphics As Graphics = Graphics.FromImage(new Bitmap(1,1))

[pax]

You could also use _lbl.CreateGraphics, but that is not important.

The important thing is, that you need a layout rectangle in your measurestring. If don't have that, the measurestring doesn't know about you fixed with, so the height will always be the height of 1 line.
If you use a layoutrectangle (the height of this does not matter) it will know the width to use, and give you the right height.
You could also add a StringFormat, to instruct it how to divide the lines and words and such.

Did that make any sense at all?
If not, let me know. I can try to elaborate further

[pax]

I just found out, that you don't need a rectangle.
The width will suffice.

Dim G As Graphics = Me.CreateGraphics
        Dim txtSize As SizeF
        Dim sf As New StringFormat
 
        sf.Alignment = StringAlignment.Center
        sf.LineAlignment = StringAlignment.Center
 
        txtSize = G.MeasureString("A very long text that will probably be too long to fit into 50 pixels", Me.Font, 50, sf)

[mendhak]

Great, thanks a lot. Today is a good day.

I ended up using this:

Dim G As Graphics = _lbl.CreateGraphics
            Dim txtSize As SizeF
            Dim sf As New StringFormat
            sf.Alignment = StringAlignment.Center
            sf.LineAlignment = StringAlignment.Center
            txtSize = G.MeasureString(.Text, _lbl.Font, 250, sf)
            Dim _lblSize_Height As Single
            Dim _lblSize_Width As Single
            _lblSize_Height = txtSize.Height
            _lblSize_Width = txtSize.Width
            .Size = New System.Drawing.Size(_lblSize_Width, _lblSize_Height)

[pax]