/// <summary>
/// Method called at compile-time by the weaver just before the instance is serialized.
/// </summary>
/// <param name="method">Method on which this instance is applied.</param>
/// <remarks>
/// <para>Derived classes should implement this method if they want to compute some information
/// at compile time. This information to be stored in member variables. It shall be
/// serialized at compile time and deserialized at runtime.
/// </para>
/// <para>
/// You cannot store and serialize the <paramref name="method"/> parameter because it is basically
/// a runtime object. You shall receive the <see cref="MethodBase"/> at runtime by the
/// <see cref="RuntimeInitialize"/> function.
/// </para>
/// </remarks>
public override bool CompileTimeValidate(MethodBase method)
{
bool hasError = false;
// Cannot be a constructor.
MethodInfo methodInfo = method as MethodInfo;
if (methodInfo == null)
{
DbInvokeMessageSource.Instance.Write(SeverityType.Error, "DBI0001",
new object[] { method.DeclaringType.FullName });
return(false);
}
// Should have void return type.
if (methodInfo.ReturnType != typeof(void))
{
DbInvokeMessageSource.Instance.Write(SeverityType.Error, "DBI0002",
new object[] { method.ToString() });
hasError = true;
}
// All parameters should be mappable.
foreach (ParameterInfo parameter in methodInfo.GetParameters())
{
Type parameterType = parameter.ParameterType;
if (parameterType.IsByRef)
{
parameterType = parameterType.GetElementType();
}
if (DbTypeMapping.GetPreferredMapping(parameterType) == null)
{
DbInvokeMessageSource.Instance.Write(SeverityType.Error, "DBI0003",
new object[]
{
method.ToString(), parameter.ParameterType.FullName,
parameter.Name
});
hasError = true;
}
}
return(!hasError);
}
/// <summary>
/// Method called instead of the body of the modified method. We put our own implementation
/// here: calling the stored procedure that has the same name and signature as the
/// called method.
/// </summary>
/// <param name="aspectArgs">Event arguments specifying which method is being
/// executed, on which object instance and with which parameters.
/// <remarks>
public override void OnInvoke(MethodInterceptionArgs args)
{
// Get a connection.
DbConnection connection = dbProviderFactory.CreateConnection();
connection.ConnectionString = this.connectionString;
// Get a command and set it up.
DbCommand command = connection.CreateCommand();
command.CommandText = args.Method.Name;
command.CommandType = CommandType.StoredProcedure;
// Add parameters.
ParameterInfo[] methodParameters = args.Method.GetParameters();
for (int i = 0; i < methodParameters.Length; i++)
{
ParameterInfo methodParameter = methodParameters[i];
// If the parameter is ByRef, get the element type.
Type parameterType = methodParameter.ParameterType;
if (parameterType.IsByRef)
{
parameterType = parameterType.GetElementType();
}
// Create and set up the parameter.
DbParameter commandParameter = dbProviderFactory.CreateParameter();
commandParameter.ParameterName = methodParameter.Name;
if (methodParameter.ParameterType.IsByRef)
{
if (methodParameter.IsIn && methodParameter.IsOut)
{
commandParameter.Direction = ParameterDirection.InputOutput;
}
else
{
commandParameter.Direction = ParameterDirection.Output;
}
}
else
{
commandParameter.Direction = ParameterDirection.Input;
}
DbCompactType dbType = DbTypeMapping.GetPreferredMapping(parameterType).DbCompactType;
commandParameter.DbType = dbType.DbType;
commandParameter.Size = dbType.Size == DbTypeMapping.FreeSize ? 1000 : dbType.Size;
// If the parameter is input, set its value.
if (methodParameter.IsIn || methodParameter.Attributes == ParameterAttributes.None)
{
commandParameter.Value = args.Arguments[i];
}
// Finally add the parameter to the command.
command.Parameters.Add(commandParameter);
}
connection.Open();
try
{
// Execute the command.
command.ExecuteNonQuery();
// Write back the output parameters.
for (int i = 0; i < methodParameters.Length; i++)
{
ParameterInfo methodParameter = methodParameters[i];
if (methodParameter.ParameterType.IsByRef)
{
args.Arguments[i] =
Convert.ChangeType(command.Parameters[i].Value,
methodParameter.ParameterType.GetElementType());
}
}
}
finally
{
connection.Close();
}
}
