SqlMembershipProvider.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 the user name associated with the specified email address.

public:
 override System::String ^ GetUserNameByEmail(System::String ^ email);

public override string GetUserNameByEmail (string email);

override this.GetUserNameByEmail : string -> string

Public Overrides Function GetUserNameByEmail (email As String) As String

Parameters

email: String

The email address to search for.

Returns

String

The user name associated with the specified email address. If no match is found, this method returns null.

Exceptions

ArgumentException

email exceeds 256 characters.

ProviderException

More than one user with the same email address exists in the database and RequiresUniqueEmail is true.

Examples

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

Note

This example uses the Membership class to call the SqlMembershipProvider specified as the defaultProvider in the Web.config file. If you need to access the default provider as the type SqlMembershipProvider, you can cast the Provider property of the Membership class. To access other configured providers as a specific provider type, you can access them by their configured name with the Providers property of the Membership class and cast them as the specific provider type.

<%@ 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

This method is called by the Membership class with an email address, which it uses to retrieve an associated user name from the SQL Server database specified in the ASP.NET application's configuration file (Web.config).

If more than one user in the membership database has the same email address, the first user name encountered is returned. You can set the requiresUniqueEmail attribute to true in the application-configuration file to ensure that each email address in the database is unique.

Leading and trailing spaces are trimmed from the email parameter value.

Applies to

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