How to add a custom property?

Question

Dear All,

On another thread (see https://learn.microsoft.com/en-us/answers/questions/1494052/how-to-add-custom-properties-in-default-controls?source=docs), Jose Pablo Ramirez gave me the answer.

Yes, one can further add to controls as they are just classes, like any other class. Create a new class and derive from TextBox:

C#

Copy
public class MyTextBox : TextBox
{
    [Browsable(true)]
    public string AllCapsText
        => Text.ToUpper();
}

Then I ask him for a comment.

1. Create a new project "ControlLibrary" and add your class to the project, i.e., right-click on the project name and choose Add->Class. On the code window of the new class, paste the code you provided.
2. Add the new project "ControlLibrary" to my project "NewTims".
3. Drag "MyTextBox" from the Toolbox to a form of my project "NewTims"
4. I find the Property "AllCapsText" gray. When I press "Start" to run the form and enter text to the "myTextBox1", the text does not automatically turn capital.
   

Then I ask him "How to solve the problems?". However, so far I haven't received any reply. I didn't know if he didn't receive my comment. Since I typed @José Pablo Ramirez, normally after I entered "@J" a popup menu will be shown. However, when on this popup menu, I didn't find his name. Therefore I didn't know if he received my comment. If you can solve my problem, please help. TIA

Answer 1

Hi @BenTam-3003 , Welcome to Microsoft Q&A,

What you want and what you asked are not the same in the previous question.

I have carefully analyzed your current problem. You need to add a textchange event in the textbox to change the case. The specific code is as follows:

using System;
using System.Windows.Forms;

namespace xxxx
{
    public partial class MyTextBox : TextBox
    {
        private bool allCapsText;
        public MyTextBox()
        {
            InitializeComponent();
            this.TextChanged += MyTextBox_TextChanged;
        }
        private void MyTextBox_TextChanged(object sender, EventArgs e)
        {
            if (AllCapsText)
            {
                int selectionStart = this.SelectionStart;
                int selectionLength = this.SelectionLength;

                this.Text = this.Text.ToUpper();

                this.SelectionStart = selectionStart;
                this.SelectionLength = selectionLength;
            }
        }

        public bool AllCapsText
        {
            get { return allCapsText; }
            set { allCapsText = value; }
        }
        protected override void OnPaint(PaintEventArgs pe)
        {
            base.OnPaint(pe);
        }
    }
}

Best Regards,

Jiale

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