Access a form in asp.NET C#
<form action="login.aspx" method="get">
    <p>Username: <input type="text" name="username" /></p>
    <p>Password: <input type="text" name="password" /></p>
    <input type="submit" value="Submit" />
</form>

Dim UserName
UserName = Request.Form("UserName")

string userName = Request.Form["UserName"];

<form action="login.aspx" method="post">

<form action="login.aspx" method="post" runat="server">
    <p>Username: <input type="text" name="username" runat="server" id="txtUsername" /></p>
    <p>Password: <input type="text" name="password" runat="server" id="txtPassword"/></p>
    <input type="submit" value="Submit" />
</form>

string UserName= txtUsername.Value;