CODEWITHSUNDEEP
vb.netwinforms
Lou
Lou

Reputation: 2519

Resize RichTextBox according to number of lines and font size

I have a RichTextBox on VB.NET Winforms, and I want it to display (say) 12 lines of text in Liberation Mono 10pt font. I can resize it manually of course, but I want to programmatically resize it according to the font size and number of lines. The thing I'm struggling with is how to work out the height of a single line. I tried:

RichTextBox.Height = RichTextBox.Font.Height

and:

RichTextBox.Height = RichTextBox.Font.GetHeight

But neither seemed to give me the exact dimensions I wanted. Is there a way to measure the exact height of a line in a RTB?

Thanks @Arman, I did this in the end:

Public Function GetHeightOfFirstNumLines(ByVal RTB As RichTextBox, ByVal NumLines As Integer) As Integer
    Dim Position1 = RTB.GetPositionFromCharIndex(RTB.GetFirstCharIndexFromLine(0))
    Dim Position2 = RTB.GetPositionFromCharIndex(RTB.GetFirstCharIndexFromLine(NumLines))
    Return Position2.Y - Position1.Y
End Function

Then in the Form.Load event, this code:

Dim RTBSize As New Size(TextRenderer.MeasureText("M", MemoryRtb.Font, MemoryRtb.Size, TextFormatFlags.WordBreak))
    MemoryRtb.ClientSize = New Size(MemoryRtb.ClientSize.Width, (RTBSize.Height * 11) + 5)

Upvotes: 0

Views: 4084

Answers (2)

GSerg
GSerg

Reputation: 78210

Lines can have different height, so you can do something like this:

Private Shared Function GetHeightOfFirstLines(ByVal Rtb As RichTextBox, ByVal NumLines As Integer) As Integer
    Dim p1 = Rtb.GetPositionFromCharIndex(Rtb.GetFirstCharIndexFromLine(0))
    Dim p2 = Rtb.GetPositionFromCharIndex(Rtb.GetFirstCharIndexFromLine(NumLines))

    Return p2.Y - p1.Y
End Function

Then

RichTextBox1.ClientSize = New Size(RichTextBox1.ClientSize.Width, GetHeightOfFirstLines(RichTextBox1, 10))

This however requires that you already have 10 lines of text in the textbox. If you don't, you can get the height of the first line and assume the future ten lines will be of same height:

RichTextBox1.ClientSize = New Size(RichTextBox1.ClientSize.Width, GetHeightOfFirstLines(RichTextBox1, 1) * 10)

Upvotes: 1

Arman
Arman

Reputation: 1442

Use TextRenderer.MeasureText()

Dim rtbSize As New Size(TextRenderer.MeasureText(RichTextBox1.Text, RichTextBox1.Font, RichTextBox1.Size, TextFormatFlags.WordBreak))

RichTextBox1.Height = rtbSize.Height + 10

Upvotes: 2

Related Questions