Sign in to follow this  

[.net] How to detect "\n" character in a line in a textBox?

This topic is 3583 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Hi, I am developing a text comparer application. How to detect if there is an empty line in the textBox? I have tried with the method String::IsNullOrEmpty and detect if the line is equal to "\n" but it still don't work.. How to do that? I am using Visual C++ and .Net 2.0. Thank you very much.

Share this post


Link to post
Share on other sites
If the textbox is multiline you could get the lines (with the Lines property) and cicle over them to find a string with 0 lenght (I think that the textbox automatically removes the \n at the end of each line):

TextBox box = new TextBox();
box.Text = "This is a \n multiline textbox\n\nwith an empty string?";
box.Multiline = true;
Console.WriteLine(box.Lines.Length);
foreach(String s in box.Lines)
{
if (s.Length == 0) Console.WriteLine("found");
}




This seems to work.

Share this post


Link to post
Share on other sites
Ok, then I will try yours. I have tried to check it out with String::IsNullOrEmpty or is it equal to "\n" or not.

And also if I have found that empty line, I want to highlight it as a empty line so the highlight contains nothing but a single line from left edge to right edge. And also if the line contains any character, I only can select from the first character to the last character only, not full line.

How to do full line selection like that?

Thank you very much..

Share this post


Link to post
Share on other sites
I don't know if there is an easy way to do that. I would override the Paint method and draw the selected line myself as a rectangle at the specified position. Getting the correct position could become a bit tricky perhaps, but should be doable.

Share this post


Link to post
Share on other sites
No, I never did it, but you can try by overriding the Paint method and using the Graphic object it provides. Try drawing something (like a circle or something like this) using this object and the drawing methods it offers. If you can do that, then you may try drawing a coloured rectangle where there is the blank line. You will have to take into account font size, window size and scroll position and honestly I don't really know how you should take all this into account.
Start by drawing some shapes on the graphic object, perhaps this will be of inspiration for you :-)

Share this post


Link to post
Share on other sites

This topic is 3583 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this