Export (0) Print
Expand All

RoleProvider.RoleExists Method

Gets a value indicating whether the specified role name already exists in the role data source for the configured applicationName.

Namespace:  System.Web.Security
Assembly:  System.Web (in System.Web.dll)

public abstract bool RoleExists(
	string roleName
)

Parameters

roleName
Type: System.String

The name of the role to search for in the data source.

Return Value

Type: System.Boolean
true 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 override bool RoleExists(string rolename)
{
  if (rolename == null || rolename == "")
    throw new ProviderException("Role name cannot be empty or null.");

  bool exists = false;

  OdbcConnection conn = new OdbcConnection(connectionString);
  OdbcCommand cmd = 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();

    int numRecs = (int)cmd.ExecuteScalar();

    if (numRecs > 0)
    {
      exists = true;
    }
  }
  catch (OdbcException)
  {
    // Handle exception.
  }
  finally
  {
    conn.Close();      
  }

  return exists;
}

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0

Community Additions

ADD
Show:
© 2014 Microsoft