how to apply validation on text box in window application...?

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 WindowsFormsApplication21 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { foreach (Control cnt in this.Controls) { if (cnt is TextBox) { if (cnt.Text == "") { MessageBox.Show("TextBox is Blank."); cnt.BackColor = Color.Pink; } } } } } }

Hi Sunder, Try this... 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 WindowsFormsApplication1 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { if (textBox1.Text == "" || textBox2.Text == "" || textBox3.Text == "" || textBox4.Text == "" || textBox5.Text == "" || textBox6.Text == "" || textBox7.Text == "" || textBox8.Text == "" || comboBox1.Text == "" || comboBox2.Text == "" || comboBox3.Text == "" || comboBox4.Text == "") { MessageBox.Show("Fields cannnot be blank"); } else { MessageBox.Show("Insert"); } } } } } 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 WindowsFormsApplication21 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { foreach (Control cnt in this.Controls) { if (cnt is TextBox) { if (cnt.Text == "") { MessageBox.Show("TextBox is Blank."); cnt.BackColor = Color.Pink; } } } } } } Method-3 private void btnSave_Click(object sender, EventArgs e) { ErrorTracker et = new ErrorTracker(errorProvider1); if (TextBox1.Text.Trim() == "") { et.SetError(TextBox1, "Required !"); } if (TextBox2.Text.Trim() == "") { et.SetError(TextBox2, "Required !"); } if (TextBox3.Text.Trim() == "") { et.SetError(TextBox3, "Required !"); } if (TextBox4.Text.Trim() == "") { et.SetError(TextBox4, "Required !"); } int a = et.Count; if (!(a > 0)) { errorProvider1.Clear(); this.SavePatientMessage(); } } Thanks If this post helps you mark it as answer

You will need to write your own validations and execute them either on something like a button click event or on a text changed event. You can limit some errors in the UI, for example if you are looking for an input of 12 characters or less you set the maximum size of the textbox to 12 using that property. If you want to do something like validate an email address you can use a regular expression to test the contents of the textbox to make sure it is compliant. How you display the error is also up to you, you can use a message box to provide the user with instructions or you can mark the textbox by exposing a previously hidden character or something of that nature.