Membership.GetUserNameByEmail(String) Method

Reference

Definition

Namespace:: System.Web.Security

Assembly:: System.Web.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Gets a user name where the email address for the user matches the specified email address.

public:
 static System::String ^ GetUserNameByEmail(System::String ^ emailToMatch);

public static string GetUserNameByEmail (string emailToMatch);

static member GetUserNameByEmail : string -> string

Public Shared Function GetUserNameByEmail (emailToMatch As String) As String

Parameters

emailToMatch: String

The email address to search for.

Returns

String

The user name where the email address for the user matches the specified email address. If no match is found, null is returned.

Examples

The following code example retrieves the user name for a specified email address.

Important

This example contains a text box that accepts user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview.

<%@ Page Language="C#" %>
<%@ Import Namespace="System.Web.Security" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

public void Search_OnClick(object sender, EventArgs args)
{
  string username = Membership.GetUserNameByEmail(EmailTextBox.Text);

  if (username == null)
  {
    Msg.Text = "Email address " + Server.HtmlEncode(EmailTextBox.Text) + " is not found. Please reenter.";
  }
  else
  {
    Msg.Text = "The user name for " + Server.HtmlEncode(EmailTextBox.Text) + 
               " is " + Server.HtmlEncode(username) + ".";
  }

}

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Sample: Retrieve Username By Email</title>
</head>
<body>

<form id="form1" runat="server">
  <h3>Forgot your Username? Search for it by email address.</h3>

  <asp:Label id="Msg" runat="server" ForeColor="maroon" /><br />

  Email address: <asp:Textbox id="EmailTextBox" Columns="30" runat="server" />
                  <asp:RequiredFieldValidator id="EmailRequiredValidator" runat="server"
                                        ControlToValidate="EmailTextBox" ForeColor="red"
                                        Display="Static" ErrorMessage="Required" /><br />

  <asp:Button id="SearchButton" Text="Search" 
              OnClick="Search_OnClick" runat="server" />

</form>

</body>
</html>

<%@ Page Language="VB" %>
<%@ Import Namespace="System.Web.Security" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

Public Sub Search_OnClick(sender As Object, args As EventArgs)

  Dim username As String = Membership.GetUserNameByEmail(EmailTextBox.Text)

  If username Is Nothing Then
    Msg.Text = "Email address " & Server.HtmlEncode(EmailTextBox.Text) & " is not found. Please reenter."
  Else
    Msg.Text = "The user name for " & Server.HtmlEncode(EmailTextBox.Text) & _
               " is " & Server.HtmlEncode(username) & "."
  End If

End Sub

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Sample: Retrieve Username By Email</title>
</head>
<body>

<form id="form1" runat="server">
  <h3>Forgot your Username? Search for it by email address.</h3>

  <asp:Label id="Msg" runat="server" ForeColor="maroon" /><br />

  Email address: <asp:Textbox id="EmailTextBox" Columns="30" runat="server" />
                  <asp:RequiredFieldValidator id="EmailRequiredValidator" runat="server"
                                        ControlToValidate="EmailTextBox" ForeColor="red"
                                        Display="Static" ErrorMessage="Required" /><br />

  <asp:Button id="SearchButton" Text="Search" 
              OnClick="Search_OnClick" runat="server" />

</form>

</body>
</html>

Remarks

GetUserNameByEmail can be used to retrieve the user name for a membership user in the case where a user does not know their user name, but does know their email address. If more than one user in the data store has the same email address, the first user name encountered is returned.

Leading and trailing spaces are trimmed from all parameter values.

Applies to