/// <summary>
/// Builds a new instance of the class <see cref="DbTypeMapping"/>.
/// </summary>
/// <param name="clrType">CLI type.</param>
/// <param name="dbType">Database type.</param>
/// <param name="preference">Preference (higher is better).</param>
protected DbTypeMapping(Type clrType, DbCompactType dbType, int preference)
{
if (clrType == null)
{
throw new ArgumentNullException("clrType");
}
this.clrType = clrType;
this.dbType = dbType;
this.preference = preference;
}
/// <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();
}
}
