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c# - How to check if a StringBuilder is empty

c# example - stringbuilder check if empty
The following ASP.NET C# example code demonstrate us how can we determine whether a Stringbuilder objectis empty or contain any characters. .Net framework's StringBuilder Class represent a mutable string of characters.StringBuilder class cannot be inherited.

StringBuilder and String both objects represent sequences of characters, but they are implemented differently. String is animmutable type and StringBuilder is a mutable type. So, each operation that appears to modify a String object actuallycreate and return a new String but each operation to modify a StringBuilder object return the same StringBuilder objectas modified.

.Net framework's StringBuilder.Length property allow us to get the length of the current Stringbuilder object. This propertyreturn a System.Int32 value. Returned integer value represent the length of StringBuilder instance.

So, we can check whether a StringBuilder object is empty by using its Length property. If StringBuilder.Length propertyreturn zero (0) then we can determine the StringBuilder object is empty (no character exist in StringBuilder). If it returngreater than zero then we can understand that StringBuilder object is not empty and it has one or more characters.
stringbuilder-check-if-empty.aspx

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

<!DOCTYPE html>

<script runat="server"> 
    protected void Button1_Click(object sender, System.EventArgs e)  
    {
        StringBuilder stringb = new StringBuilder();
        StringBuilder stringb2 = new StringBuilder();
        stringb.Append("this is first stringbuilder.");

        Label1.Text = "first stringbuilder: " + stringb.ToString();
        Label1.Text += "<br />second stringbuilder: " + stringb2.ToString() + "<br />";

        int lenght1 = stringb.Length;
        int lenght2 = stringb2.Length;

        if (lenght1 == 0)
        {
            Label1.Text += "<br />first stringbuilder is empty";
        }
        else
        {
            Label1.Text += "<br />first stringbuilder is not empty";
        }

        if (lenght2 == 0)
        {
            Label1.Text += "<br />second stringbuilder is empty";
        }
        else
        {
            Label1.Text += "<br />second stringbuilder is not empty";
        }
    }  
</script>  

<html xmlns="http://www.w3.org/1999/xhtml">  
<head id="Head1" runat="server">  
    <title>c# example - stringbuilder check if empty</title>  
</head>  
<body>  
    <form id="form1" runat="server">  
    <div>  
        <h2 style="color:MidnightBlue; font-style:italic;">  
            c# example - stringbuilder check if empty
        </h2>  
        <hr width="550" align="left" color="Gainsboro" />  
        <br />  
        <asp:Label   
            ID="Label1"   
            runat="server"  
            Font-Size="Large"  
            >  
        </asp:Label>  
        <br /><br />
        <asp:Button   
            ID="Button1"   
            runat="server"   
            Text="stringbuilder check if empty"  
            OnClick="Button1_Click"
            Height="40"  
            Font-Bold="true"  
            />  
    </div>  
    </form>  
</body>  
</html>
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