RoleProvider.RoleExists Method (String)
.NET Framework (current version)
Gets a value indicating whether the specified role name already exists in the role data source for the configured applicationName.
Assembly: System.Web.ApplicationServices (in System.Web.ApplicationServices.dll)
Parameters
- roleName
-
Type:
System.String
The name of the role to search for in the data source.
Return Value
Type: System.Booleantrue if the role name already exists in the data source for the configured applicationName; otherwise, false.
RoleExists is called by the RoleExists method of the Roles class to determine whether a role name exists in the data source for the configured ApplicationName.
If the specified role name is null or is an empty string, we recommend that your provider throw an exception.
The following code example shows a sample implementation of the RoleExists method.
Public Overrides Function RoleExists(ByVal rolename As String) As Boolean If rolename Is Nothing OrElse rolename = "" Then _ Throw New ProviderException("Role name cannot be empty or null.") Dim exists As Boolean = False Dim conn As OdbcConnection = New OdbcConnection(connectionString) Dim cmd As OdbcCommand = New OdbcCommand("SELECT COUNT(*) FROM Roles " & _ " WHERE Rolename = ? AND ApplicationName = ?", conn) cmd.Parameters.Add("@Rolename", OdbcType.VarChar, 255).Value = rolename cmd.Parameters.Add("@ApplicationName", OdbcType.VarChar, 255).Value = ApplicationName Try conn.Open() Dim numRecs As Integer = CType(cmd.ExecuteScalar(), Integer) If numRecs > 0 Then exists = True End If Catch e As OdbcException ' Handle exception. Finally conn.Close() End Try Return exists End Function
.NET Framework
Available since 2.0
Available since 2.0
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