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c# - How to check whether a string starts with letter

String starts with letter
The following asp.net c# example code demonstrate us how can we determine whether a string starts with a letterprogrammaticaly at run time in an asp.net application. .Net framework's String Class represent text as a series of Unicodecharacters. String Class has no direct method or property to determine whether a string begins with a letter (a to z).

First, we need to get the first character of a string object to verify it is a letter or not. String.ElementAt()method allow us to get the character at a specified index position from a string. So, we can get the first character of a stringby calling the ElementAt() method as this way String.ElementAt(0), because string object is zero-based index.

Char.IsLetter(Char) overloaded method indicate whether the specified Unicode character is categorized as a Unicode letter.So, we can determine the previously collected first character of a string is a letter or not by accessing the Char.IsLetter(Char)method.

Finally, we can determine whether string starts with a letter by this way String.ElementAt(0).IsLetter(). If it return'true' then string starts with letter; otherwise string is not starts with letter.
string-starts-with-letter.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 stringPlants = "1. Swamp Holly 2. Winterberry Holly";
        string stringPlants2 = "Horse Cane. Indian Paintbrush";

        Label1.Text = "string of plants..................<br />";
        Label1.Text += stringPlants;
        Label1.Text += "<br />"+stringPlants2;

        //this line get string first/begin character
        char firstCharacter = stringPlants.ToCharArray().ElementAt(0);

        //this line get string first/begin character
        char firstCharacter2 = stringPlants2.ToCharArray().ElementAt(0);

        //test character is letter or not
        Boolean isCharacterLetter = char.IsLetter(firstCharacter);
        Boolean isCharacterLetter2 = char.IsLetter(firstCharacter2);

        Label1.Text += "<br /><br />stringPlants first character: " + firstCharacter;
        Label1.Text += "<br />stringPlants2 first character: " + firstCharacter2;

        Label1.Text += "<br /><br />stringPlants starts with letter? " + isCharacterLetter.ToString();
        Label1.Text += "<br />stringPlants2 starts with letter? " + isCharacterLetter2.ToString();
    }  
</script>  

<html xmlns="http://www.w3.org/1999/xhtml">  
<head id="Head1" runat="server">  
    <title>c# example - string starts with letter</title>  
</head>  
<body>  
    <form id="form1" runat="server">  
    <div>  
        <h2 style="color:MidnightBlue; font-style:italic;">  
            c# example - string starts with letter
        </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 starts with letter"  
            OnClick="Button1_Click"
            Height="40"  
            Font-Bold="true"  
            />  
    </div>  
    </form>  
</body>  
</html>
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