In this blog we will know blank validation on textbox in windows.

Method-1

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

namespace Validation_on_textbox

{

public partial class Form1 : Form

{

public Form1()

{

InitializeComponent();

}

private void button1_Click(object sender, EventArgs e)

{

if (textBox1.Text == "")

{

MessageBox.Show("Name Field cannnot be blank");

textBox1.Focus();

}

else

{

MessageBox.Show("Correct");

}

clear();

}

private void clear()

{

textBox1.Text = "";

}

}

}

Method-2

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

namespace Validation_on_textbox

{

public partial class Form2 : Form

{

public Form2()

{

InitializeComponent();

}

private void button1_Click(object sender, EventArgs e)

{

foreach (Control c1 in this.Controls)

{

if (c1 is TextBox)

{

if (c1.Text == "")

{

MessageBox.Show("Name Field cannnot be blank");

c1.BackColor = Color.Orange;

textBox1.Focus();

}

else

{

MessageBox.Show("Correct");

c1.BackColor = Color.White;

}

}

}

clear();

}

private void clear()

{

textBox1.Text = "";

}

}

}

Method-3

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

namespace Validation_on_textbox

{

public partial class Form3 : Form

{

public Form3()

{

InitializeComponent();

}

private void button1_Click(object sender, EventArgs e)

{

if (textBox1.Text.Trim() == "")

{

errorProvider1.SetError(textBox1, "Name Field cannnot be blank");

textBox1.Focus();

}

else

{

errorProvider1.Clear();

MessageBox.Show("Correct");

}

clear();

}

private void clear()

{

textBox1.Text = "";

}

}

}