how to validate textbox that contains only numeric

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C#

Windows

i want to validate my textbox that only contains numerics values nothing else in C# windows form application

Posted 7-Feb-14 0:17am

Abhijeet pratap singh

Updated 24-Jan-17 23:57pm

Sampath Lokuge

v2

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BillWoodruff 7-Feb-14 21:59pm

In a question like this, the details are important: do you wish to allow the use of the minus-sign, of the decimal point ?

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Gitanjali Singh · Answer 1 · 2014-02-07T00:25:00

Try like this

C#

public Form1()
{
    InitializeComponent();
    txtHomePhone.KeyPress += new KeyPressEventHandler(txtHomePhone_KeyPress);
}
private void txtHomePhone_KeyPress(object sender, KeyPressEventArgs e)
{
    if (e.KeyChar >= '0' && e.KeyChar <= '9' || e.KeyChar == '') //The  character represents a backspace
    {
        e.Handled = false; //Do not reject the input
    }
    else
    {
        e.Handled = true; //Reject the input
    }
}

Refer:
validating-whether-a-textbox-contains-only-numbers[^]
validating-a-textbox-to-allow-only-numeric-values[^]

Sampath Lokuge · Answer 2 · 2014-02-07T00:24:00

Please try is as below.

C#

private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
    if (!char.IsControl(e.KeyChar)
        && !char.IsDigit(e.KeyChar)
        && e.KeyChar != '.')
    {
        e.Handled = true;
    }

    // only allow one decimal point
    if (e.KeyChar == '.'
        && (sender as TextBox).Text.IndexOf('.') > -1)
    {
        e.Handled = true;
    }
}

For more info : How do I make a textbox that only accepts numbers

Shameel · Answer 3 · 2014-02-07T00:28:00

You can write code in two ways:

1. In the Textbox's KeyPress event, tap the KeyChar and if it is not not within the range for numebers, set the KeyChar to 0.

2. In the Textbox's Validate event, Check the contents with int.TryParse or double.TryParse as the case may be and alert the user.

Doing both of the above will ensure that your textbox contains only numbers.

Hem Raj Thakur · Answer 4 · 2014-02-07T00:33:00

C#

private void amounttext_KeyDown(object sender, KeyEventArgs e)
 {
     try
     {
         string name = this.Text.ToString();
         if ((e.KeyValue >= 48 && e.KeyValue <= 57)|| e.KeyValue == 17 || e.KeyValue == 46 || e.KeyValue == 45 || e.KeyValue == 18 || e.KeyValue == 91 || e.KeyValue == 32 || e.KeyValue == 93 || e.KeyValue == 16 || e.KeyValue == 13 || e.KeyValue == 8 || e.KeyValue == 33 || e.KeyValue == 34 || e.KeyValue == 35 || e.KeyValue == 36 || e.KeyValue == 37 || e.KeyValue == 38 || e.KeyValue == 39 || e.KeyValue == 40 || e.KeyValue == 192 || e.KeyValue == 27 || e.KeyValue == 144 || e.KeyValue == 96 || e.KeyValue == 97 || e.KeyValue == 98 || e.KeyValue == 99 || e.KeyValue == 100 || e.KeyValue == 101 || e.KeyValue == 102 || e.KeyValue == 103 || e.KeyValue == 104 || e.KeyValue == 105 || e.KeyValue == 106 || e.KeyValue == 107 || e.KeyValue == 108 || e.KeyValue == 109 || e.KeyValue == 110 || e.KeyValue == 111 || e.KeyValue == 112 || e.KeyValue == 113 || e.KeyValue == 114 || e.KeyValue == 115 || e.KeyValue == 116 || e.KeyValue == 117 || e.KeyValue == 118 || e.KeyValue == 119 || e.KeyValue == 120 || e.KeyValue == 121 || e.KeyValue == 122 || e.KeyValue == 123 || e.KeyValue == 145 || e.KeyValue == 19|| e.KeyValue == 20)
         {

         }
         else
         {
             MessageBox.Show("Only numeric value is allowed !", "" + name.ToString() + "", MessageBoxButtons.OK, MessageBoxIcon.Warning);


             string varlenth = "";
             varlenth = amounttext.Text.Substring(0, amounttext.Text.Length - 1);
             amounttext.Text = varlenth;
             amounttext.Select(amounttext.Text.Length, 0);
         }
     }
     catch { }
 }

agent_kruger · Answer 5 · 2014-02-07T21:29:00

sorry if it matches with the other answers but this is quite different

public static void IsNumberic(KeyPressEventArgs e, System.Windows.Forms.TextBox Tb)
{
    if (char.IsDigit(e.KeyChar) || char.IsControl(e.KeyChar))
    {
        e.Handled = false;
    }
    else
    {
        e.Handled = true;
    }
}

ridoy · Answer 6 · 2014-02-07T21:39:00

Solution 7

Well i would like to tell you see this article here on CP:
Check If A String Value Is Numeric[^]
And for using it on button click usage you may see this one:
Validate Textbox is Numeric on ButtonClick in C#[^]

Posted 7-Feb-14 21:39pm

ridoy

Member 12967179 · Answer 7 · 2017-01-24T23:57:00

Solution 8

private void TextboxName_KeyPress(object sender, KeyPressEventArgs e)
{
if (!char.IsDigit(e.KeyChar) && e.KeyChar != (char)Keys.Back)
e.Handled = true;
}

For digits and backspace only in c#

Posted 24-Jan-17 23:57pm

Member 12967179

Updated 24-Jan-17 23:58pm

v2

Comments

Richard MacCutchan 25-Jan-17 6:13am

Please do not resurrect old questions. This one is three years old.

how to validate textbox that contains only numeric

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