Question

I have created a textBox control on run-time for my winform application. The control appears just find once the form loads up, and works great too. However, I have just run into a problem as I realize I do not know how to write the code to write to a dynamically created control.

Let’s assume I have created a button (named “Button1”) on design time. In Button1’s click event, (Button1_Click), I would like to write the word “Hello” to a textBox control that won’t be created until the application is executed. Some code below:

C# Code:

// Create the textBox control
TextBox new_textBox = null;
int x = 10;
int y = 10;
int xWidth = 300;
int yHeight = 200;

new_textBox = new TextBox();
                new_textBox.Text = controlText;
                new_textBox.Name = "textBox" + controlName;
                new_textBox.Size = new System.Drawing.Size(xWidth - 10, yHeight - 10);
                new_textBox.Location = new Point(x, y);
                new_textBox.BringToFront();
                new_textBox.Multiline = true;
                new_textBox.BorderStyle = BorderStyle.None;

// Add the textBox control to the form
this.Controls.Add(new_textBox);

The Problem:

From Button1_Click event, I cannot get in contact with a control that has not even been created yet. Thus, Visual Studio will throw an obvious error that the control does not exist (because it doesn’t).

So, is there some way to dynamically call a control, and more
specifically, a textBox control?

Thank you for any help on the matter,

Evan

Answer 1

Declare the new_textBox at class scope. Then the compiler can access it. For example:

class MyForm
{
    TextBox new_textBox;

    void InitializeTextBox()
    {
        new_textBox = new TextBox();
        // initialization code here
        // Add it to the form
        this.Controls.Add(new_textBox);
    }

    void Button1_Click(...)
    {
        new_textBox.Text = "clicked";
    }