How to determine the width of a single character in TextBox?

[Guest]

I am writing a Windows Forms application using Visual Studio.NET in C#. I am creating a control derived from TextBox that will need to invoke a block cursor (caret) during certain edit modes. The derived control is intended to contain numeric values; integers and floating point. I understand how to create and position a caret using CreateCaret() and SetCaretPos(), available in user32.dll.

The control's font may vary from instance to instance so I want to make the caret have the correct width and height. I can get the height of the font by using either the TextBox.FontHeight property or the Font.Height property. However, I have not found a way to get the width of a character so that I can size the caret width appropriately. Since the control can contain a decimal point and a minus sign I would really like to determine the width of any individual character so that the caret does not overlap adjacent characters.

How can I determine the width of a character at a given position in a TextBox?

Thanks,
Dave

 

[Herfried K. Wagner [MVP]]

I am writing a Windows Forms application using Visual Studio.NET in C#. I am creating a control derived from TextBox that will need to invoke a block cursor (caret) during certain edit modes. The derived control is intended to contain numeric values; integers and floating point. I understand how to create and position a caret using CreateCaret() and SetCaretPos(), available in user32.dll.

P/invoke on 'DrawText' + 'DT_CALCRECT' ('DT_WORDBREAK').

 

[Ying-Shen Yu[MSFT]]

Hi Babel,

You may use Graphics.MeasureString to get the width of a string in a
certain font format. Basically you needn't mesure each single character,
just measure the string before the caret should get the x offset for the
caret. For more information you may read the doc of Graphics.MeasureString
method.

Let me know if you have anything unclear about this issue.

Have a nice day!

Best regards,

Ying-Shen Yu [MSFT]
Microsoft Community Support
Get Secure! - www.microsoft.com/security

This posting is provided "AS IS" with no warranties and confers no rights.
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before sending mail.

 

[Herfried K. Wagner [MVP]]

* (e-mail address removed) ("Ying-Shen Yu[MSFT]") scripsit:

You may use Graphics.MeasureString to get the width of a string in a
certain font format. Basically you needn't mesure each single character,
just measure the string before the caret should get the x offset for the
caret. For more information you may read the doc of Graphics.MeasureString
method.

'MeasureString' will AFAIK use GDI+ to measure the string, but the
string is drawn using GDI, which will return slightly different results.

 

[Herfried K. Wagner [MVP]]

What does "AFAIK" mean?

AFAIK = As far as I know.

Can you quantify "return slightly different results"?

Some pixels difference, depending on the font.

 

[Ying-Shen Yu[MSFT]]

Hi,

I think I missed this difference.
Thanks for pointing it out, Herfried!

Best regards,

Ying-Shen Yu [MSFT]
Microsoft Community Support
Get Secure! - www.microsoft.com/security

This posting is provided "AS IS" with no warranties and confers no rights.
This mail should not be replied directly, please remove the word "online"
before sending mail.