In-depth Guide to C# Control Programming: Text Box (TextBox)

The TextBox is a common control used in C#, allowing users to input and display text in Windows form applications. It enables functions such as user input, data display, and password input.

1. Create a text box control
   In a Windows form application, you can use Visual Studio’s designer to create a text box control. Simply select the TextBox control from the toolbox in the designer, and then click the left mouse button on the form to create a text box control.
2. Set the properties of the text box
   Various properties of the text box, such as size, position, text content, font, background color, and foreground color, can be set through the properties window. Relevant properties can be adjusted to meet the requirements of the application.
3. Accessing and setting the text content of a text box
   You can use the Text property to access and set the text content of a text box. For example, you can use textBox1.Text to get or set the text content of the textBox1 control.
4. Respond to text box events
   Text box controls provide several events that can be used to respond to user actions. Common events include TextChanged, KeyPress, KeyUp, etc. For example, you can use the textBox1.TextChanged event to execute a certain action when the text box content is changed.
5. Common methods and events of a text box.

1. Clear(): clear the content in the text box.
2. SelectAll(): Select all the content in the text box.
3. Copy(): Copy the selected content in the text box to the clipboard.
4. Paste(): Copy the content from the clipboard and paste it into the text box.
5. KeyPress event: occurs when a user presses a character on the keyboard.
6. The TextChanged event occurs when the text content of a text box is changed.

1. Enable password input mode in the text box by setting the PasswordChar property of the TextBox control. Common password characters include “*”, “●”, and others.

Summary: The text box is one of the commonly used controls in C#, used for receiving and displaying user input text. By setting properties, handling events, and calling methods, various functions of the text box can be achieved. In practical applications, the text box control can be flexibly utilized to meet user needs.