Sometime
it is required to check the value entered in textbox is numeric or not. In this
article i will explain how to check whether
entered value is numeric/number or not in asp.net
using regular
expression in both C# and
VB languages.
We can check value by using regular expression in
server side code or we can also check data type by using compare validator (Asp.NET
validator).
In this article I will use server side code to check
the data type of the input value.
Asp.Net
C# Section
Design Section:
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form
id="form1"
runat="server">
<div>
<div>
<fieldset
style="width:350px;">
<legend><strong>Check String is numeric or not</strong></legend>
<center>
<table>
<tr>
<td>
</td>
<td>
</td>
<td>
</td>
</tr>
<tr>
<td>
Enter Value</td>
<td>
<asp:TextBox ID="txtTest"
runat="server"></asp:TextBox>
</td>
<td>
</td>
</tr>
<tr>
<td>
</td>
<td>
<asp:Button ID="btnTest" runat="server" onclick="btnTest_Click"
Text="Test String" /><br />
<asp:Label ID="lblStatus" runat="server"></asp:Label>
</td>
<td>
</td>
</tr>
</table>
</center>
</fieldset>
</div>
</div>
write the
code as:
protected void btnTest_Click(object sender, EventArgs e)
{
if (IsNumeric(txtTest.Text.Trim()))
{
lblStatus.Text = txtTest.Text + " is Numeric";
lblStatus.ForeColor = System.Drawing.Color.Green;
}
else
{
lblStatus.Text = txtTest.Text + " is
not Numeric";
lblStatus.ForeColor = System.Drawing.Color.Green;
}
}
System.Text.RegularExpressions.Regex reg = new System.Text.RegularExpressions.Regex(@"^[0-9]+$");
public bool IsNumeric(String str)
{
try
{
if (string.IsNullOrEmpty(str))
{
return false;
}
if (!reg.IsMatch(str))
{
return false;
}
}
catch (Exception ex)
{
lblStatus.Text = "Error
occured : " +
ex.Message.ToString();
lblStatus.ForeColor = System.Drawing.Color.Red;
}
return true;
}
Asp.Net
VB section:
Design Section:
<div>
<fieldset style="width:200px;">
<legend>Check String is numeric or not</legend>
<center>
<table>
<tr>
<td>
<asp:TextBox ID="txtTest" runat="server"></asp:TextBox>
</td>
</tr>
<tr>
<td>
<asp:Button ID="btnTest" runat="server" Text="Test String" /><br />
<asp:Label ID="lblStatus" runat="server"></asp:Label>
</td>
</tr>
</table>
</center>
</fieldset>
</div>
write the
code as:
Protected Sub btnTest_Click(sender As Object, e As System.EventArgs) Handles btnTest.Click
If IsNumeric(txtTest.Text.Trim()) Then
lblStatus.Text = txtTest.Text + " is Numeric"
lblStatus.ForeColor = System.Drawing.Color.Green
Else
lblStatus.Text = txtTest.Text + " is
not Numeric"
lblStatus.ForeColor = System.Drawing.Color.Green
End If
End Sub
Private reg As New System.Text.RegularExpressions.Regex("^[0-9]+$")
Public Function IsNumeric(str As [String]) As Boolean
Try
If String.IsNullOrEmpty(str) Then
Return False
End If
If Not reg.IsMatch(str) Then
Return False
End If
Catch ex As Exception
lblStatus.Text = "Error
occured : " &
ex.Message.ToString()
lblStatus.ForeColor = System.Drawing.Color.Red
End Try
Return True
End Function
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