How to use AutoPostBack in asp.net TextBox

AutoPostBack feature in TextBox
AutoPostBack property indicate whether an automatic postback to the server occurs when specified control loses it's focus. asp.net textbox web server control support AutoPostBack property. so you can set it value true to postback to the server when textbox loses it's focus. simply when textbox text changes it postback to the server. AutoPostBack is work with TextChanged event. set the AutoPostBack property value true if you use TextChanged event on textbox server control. if you want to manually submit form by button click or any other event then set the textbox AutoPostBack property value false. the following example demonstrate you how can we use textbox AutoPostBack property.
TextBoxAutoPostBack.aspx

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

<!DOCTYPE html>

<script runat="server">
    protected void TextBox1_TextChanged(object sender, System.EventArgs e)
    {
        Label1.Text = "Your favorite river " + TextBox1.Text;
    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
    <title>How to use AutoPostBack feature in TextBox</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <h2 style="color:Red">TextBox Example: AutoPostBack</h2>
        <asp:Label 
             ID="Label1" 
             runat="server"
             Font-Size="X-Large"
             Font-Italic="true"
             ForeColor="DodgerBlue"
             >
        </asp:Label>
        <br /><br />
        <asp:Label 
             ID="Label2" 
             runat="server"
             Text="Favorite River"
             >
        </asp:Label>
        <asp:TextBox 
             ID="TextBox1" 
             runat="server"
             BackColor="LavenderBlush"
             AutoPostBack="true"
             OnTextChanged="TextBox1_TextChanged"
             >
        </asp:TextBox>
    </div>
    </form>
</body>
</html>
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