How do I override the normal maxlength for a custom textbox control and make it un-editable? C#

Question

0.00/5 (No votes)

See more:

Hi! I am creating a custom TextBox Control, where I will give it a custom, non-editable Maximum Length. (2147483647 is the custom MaxLength)

Basically, I need to completely remove the MaxLength Property, and replace it with my own MaxLength.

I just don't know how to remove the MaxLength and replace it with my Maximum Length Property.

What I have tried:

private int length = 2147483647;

        [Browsable(true)]
        [Category("Custom Behavior")]
        [Description("The maximum length for the control. This is a read-only property.")]
        [DisplayName("Maximum Length")]

        public int MaximumLength
        {
            get { return this.length; }
        }

Posted 10-Feb-20 19:30pm

The Magical Magikarp

Updated 11-Feb-20 2:50am

Add a Solution

3 solutions

Solution 1

You can't, not unless you create an entirely new TextBox-like control form a UserControl and allow am much, much larger-than-standard Length.

But it's not a good idea, even if you could (or you go to all the effort involved in "rolling your own" TextBox).
Think about it: 2,147,483,647 characters is around 27,000,000 lines of text. Do you seriously intend to slap that much text down in front of the user and say "right - you get on with it"? The system will probably slow to a crawl - assuming it doesn't just stop entirely - and your user will have no good way to even read it. I can get around 110 lines of text on my screen at a comfortable reading size, so you are looking at around 250,000 pages of text in a single control, assuming it fills the screen. Just how big do you think the scroll bar tab is going to be? how long will it take the user to wade through that lot looking for the one page - or worse one line - he is looking for?

It's a dumb idea: your users will hate it and by extension your app and you. Sit down, and rethink your entire UI for a user perspective rather than "easy for me to code" - it's completely broken at present.

Posted 10-Feb-20 20:10pm

OriginalGriff

Comments

The Magical Magikarp 11-Feb-20 2:15am

Well, I have a 'Find' and 'Replace' option, which would allow them to find the text they wish & replace it.. It also allows them to travel to the selected line. (Which is organized by pages) So, the answer is No?

johannesnestler 11-Feb-20 10:04am

So implement exactly that. Persist the "string" - it should be a file. Show the user the search results from the file, let them replace/jump (Maybe get an inspiration from Notepad++ "search and replace in multiple files" feature). Make a Control to show the changed lines (whatever). But DON'T load the whole text to a Control. Only think about memory consumtion (and everything OriginalGriff mentioned). Really rethink what you want to do, The feature can't be "I show you now million lines of text).
I did a Trace-Viewer back than (full verbosity Level the application (backend/frontend) generated About 400k lines of trace for a single click), that worked like that. But not for a second I thought: Ah I just load the whole thing....

The Magical Magikarp 11-Feb-20 2:18am

Also, could you point me in the right direction for creating my own entirely new TextBox from a UserControl? Thanks :)

Solution 3

Why would you want to do this? The existing MaxLength of the TextBox also reflects the actual maximum length of a string in bytes. You can't make a MaxLength property larger and have it work. You can't create a string bigger than Int32.MaxValue bytes or characters in length. So, what's the point?

Posted 11-Feb-20 2:51am

Dave Kreskowiak

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

phil.o · Accepted Answer · 2020-02-11T01:36:00

Solution 2

Technically, by inheriting TextBox, you can shadow its MaxLength property with the new keyword:

C#

public class CustomTextBox : TextBox
{
   public new int MaxLength
   {
      get { /* ... */ }
   }
}

If you do not provide any setter, the new property will be read-only.

But, as Paul stated in its solution, that is a terrible idea to try to stuff so much information in a single control.

Posted 11-Feb-20 1:36am

phil.o

Updated 11-Feb-20 1:37am

v2

Comments

The Magical Magikarp 11-Feb-20 21:15pm

I liked the other answers, but yours answers my question perfectly :) Thanks!