When using forms authentication with client application services, you can pass a user name and password to the ValidateUser method. You can also pass empty strings or nullNothingnullptra null reference (Nothing in Visual Basic) as the parameters to use a credentials provider. A credentials provider is a class that you provide and specify in your application configuration. A credentials provider class must implement the IClientFormsAuthenticationCredentialsProvider interface, which has a single method called GetCredentials. A typical GetCredentials method implementation will display a dialog box to retrieve user input. Using a credentials provider enables you to share a single login dialog box among multiple applications. For more information, see How to: Implement User Login and Logout with Client Application Services.

The following example code demonstrates how to implement the GetCredentials method. In this example, the GetCredentials method is part of a login dialog box class. This method displays the dialog box, and then returns a ClientFormsAuthenticationCredentials instance initialized with the user-specified values.

Public Function GetCredentials() As  _
    ClientFormsAuthenticationCredentials Implements _
    IClientFormsAuthenticationCredentialsProvider.GetCredentials

    If Me.ShowDialog() = DialogResult.OK Then
        Return New ClientFormsAuthenticationCredentials( _
            UsernameTextBox.Text, PasswordTextBox.Text, _
            rememberMeCheckBox.Checked)
    Else
        Return Nothing
    End If

End Function

public ClientFormsAuthenticationCredentials GetCredentials()
{
    if (this.ShowDialog() == DialogResult.OK)
    {
        return new ClientFormsAuthenticationCredentials(
            usernameTextBox.Text, passwordTextBox.Text,
            rememberMeCheckBox.Checked);
    }
    else
    {
        return null;
    }
}

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

.NET Framework

Reference

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