c# - How to check whether a string contains any special character

String contains special characters
string-contains-special-characters.aspx

<%@ Page Language="C#" AutoEventWireup="true"%>

<!DOCTYPE html>  
<script runat="server"> 
    protected void Button1_Click(object sender, System.EventArgs e)  
    {
        //this section create string variables.
        string colors = "1 Red 2 green 3 blue";
        string colors2 = "#red #green #blue";
        string colors3 = "red* green* blue*";

        Label1.Text = "string..................<br />";
        Label1.Text += "colors: " + colors;
        Label1.Text += "<br />colors2: " + colors2;
        Label1.Text += "<br />colors3: " + colors3;

        //check string contains any special characters without space
        Regex rex = new Regex("^[a-z0-9 ]+$",RegexOptions.IgnoreCase);

        Boolean result = rex.IsMatch(colors);
        Boolean result2 = rex.IsMatch(colors2);
        Boolean result3 = rex.IsMatch(colors3);

        Label1.Text += "<br /><br />colors contains no special characters without space? " + result.ToString();
        Label1.Text += "<br /><br />colors2 contains no special characters without space? " + result2.ToString();
        Label1.Text += "<br /><br />colors3 contains no special characters without space? " + result3.ToString();
    }  
</script>  
  
<html xmlns="http://www.w3.org/1999/xhtml">  
<head id="Head1" runat="server">  
    <title>c# example - string contains special characters</title>  
</head>  
<body>  
    <form id="form1" runat="server">  
    <div>  
        <h2 style="color:MidnightBlue; font-style:italic;">  
            c# example - string contains special characters
        </h2>  
        <hr width="550" align="left" color="Gainsboro" />  
        <asp:Label   
            ID="Label1"   
            runat="server"  
            Font-Size="Large"
            >  
        </asp:Label>  
        <br /><br />
        <asp:Button   
            ID="Button1"   
            runat="server"   
            Text="string contains special characters"  
            OnClick="Button1_Click"
            Height="40"  
            Font-Bold="true"  
            />  
    </div>  
    </form>  
</body>  
</html>
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