Here is the English translation of the provided text:
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C# TextBox events are specific functional requirements we encounter during development. So, how do we make the desired C# TextBox events execute? Here, I will introduce you to specific examples of C# TextBox event demonstrations, including the implementation of these requirements, which I hope will be helpful to you.
### Specific Requirements for C# TextBox Events:
- **Interface Requirements**: Define 5 TEXTBOX fields: Name, Address, Occupation, Age, and Output Content. Also, include 1 BUTTON.
- **Satisfaction Conditions**:
1. The username cannot be empty.
2. The age must be a number greater than or equal to 0.
3. The occupation must be "Programmer" or left blank.
4. The address cannot be empty.
### Implementation of the C# TextBox Event Example:
```csharp
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
namespace Chapter14
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
this.button1.Enabled = false;
this.textBox1.Tag = false;
this.textBox2.Tag = false;
this.textBox3.Tag = false;
this.textBox4.Tag = false;
this.textBox1.Validating += new System.ComponentModel.CancelEventHandler(this.textboxEmpty_Validating);
this.textBox2.Validating += new System.ComponentModel.CancelEventHandler(this.textboxEmpty_Validating);
this.textBox3.Validating += new System.ComponentModel.CancelEventHandler(this.textboxOccupation_Validating);
this.textBox4.Validating += new System.ComponentModel.CancelEventHandler(this.textboxEmpty_Validating);
this.textBox1.TextChanged += new System.EventHandler(this.textbox_TextChanged);
this.textBox4.TextChanged += new System.EventHandler(this.textbox_TextChanged);
this.textBox3.TextChanged += new System.EventHandler(this.textbox_TextChanged);
}
// C# TextBox Event
private void textboxOccupation_Validating(object sender, System.ComponentModel.CancelEventArgs e)
{
TextBox tb = (TextBox)sender;
if (tb.Text.CompareTo("Programmer") == 0 || tb.Text.Length == 0)
{
tb.Tag = true;
tb.BackColor = System.Drawing.SystemColors.Window;
}
else
{
tb.Tag = false;
tb.BackColor = Color.Red;
}
ValidateOk();
}
// C# TextBox Event
private void textboxEmpty_Validating(object sender, System.ComponentModel.CancelEventArgs e)
{
TextBox tb = (TextBox)sender;
if (tb.Text.Length == 0)
{
tb.BackColor = Color.Red;
tb.Tag = false;
}
else
{
tb.BackColor = System.Drawing.SystemColors.Window;
tb.Tag = true;
}
ValidateOk();
}
private void textboxAge_KeyPress(object sender, KeyPressEventArgs e)
{
if ((e.KeyChar 57) && e.KeyChar != 8)
e.Handled = true;
}
private void textbox_TextChanged(object sender, System.EventArgs e)
{
TextBox tb = (TextBox)sender;
if (tb.Text.Length == 0 && tb != textBox3)
{
tb.Tag = false;
tb.BackColor = Color.Red;
}
else if (tb == this.textBox3 && (tb.Text.Length != 0 && tb.Text.CompareTo("Programmer") != 0))
{
tb.Tag = false;
}
else
{
tb.Tag = true;
tb.BackColor = SystemColors.Window;
}
ValidateOk();
}
private void ValidateOk()
{
this.button1.Enabled = ((bool)(this.textBox2.Tag) && (bool)(this.textBox4.Tag) && (bool)(this.textBox1.Tag) && (bool)(this.textBox3.Tag));
}
private void button1_Click(object sender, EventArgs e)
{
string output;
// C# TextBox Event
output = "Name:" + this.textBox1.Text + " ";
output += "Address:" + this.textBox2.Text + " ";
output += "Occupation:" + this.textBox3.Text + " ";
output += "Age:" + this.textBox4.Text + " ";
this.textBox5.Text = output;
}
}
}
```
### Conclusion
This is the detailed example of implementing C# TextBox events. I hope it helps you understand and learn about C# TextBox events effectively.
Original article link: [Eden Network](http://www.edenw.com/tech/devdeloper/Cp/2010-07-16/4753.html)
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This translation provides an accurate representation of the original content in English while maintaining the technical details and structure of the code.