/// <summary>
/// An attribute builder method
/// </summary>
/// <param name="attr"></param>
/// <returns></returns>
public static CustomAttributeBuilder GetCustomAttributeBuilder(SWCommandAttribute attr)
{
string commandText = attr.m_commandText;
object returnIfNull = attr.m_returnIfNull;
if (returnIfNull == null)
{
returnIfNull = NullReturnValueToken;
}
Type[] arrParamTypes = new Type[] { typeof(SWCommandType), typeof(string), typeof(object), typeof(MissingSchemaAction) };
object[] arrParamValues = new object[] { attr.m_commandType, commandText, returnIfNull, attr.m_missingSchemaAction };
ConstructorInfo ctor = typeof(SWCommandAttribute).GetConstructor(arrParamTypes);
return(new CustomAttributeBuilder(ctor, arrParamValues));
}
/// <summary>
/// Adds attributes and an implementation to a method of the created class.
/// </summary>
/// <param name="method">MethodInfo object.</param>
/// <param name="tb">Type builder object.</param>
private static void AddMethodImplementation(MethodInfo method, TypeBuilder tb)
{
// get method return type
Type RetType = method.ReturnType;
// get method paramete information
ParameterInfo [] prms = method.GetParameters();
int paramCount = prms.Length;
// get method parameter types and names
Type [] paramTypes = new Type [paramCount];
string[] paramNames = new string[paramCount];
ParameterAttributes[] paramAttrs = new ParameterAttributes[paramCount];
for (int i = 0; i < paramCount; ++i)
{
paramTypes[i] = prms[i].ParameterType;
paramNames[i] = prms[i].Name;
paramAttrs[i] = prms[i].Attributes;
}
// define method body
MethodBuilder methodBody = tb.DefineMethod(method.Name, MethodAttributes.Public | MethodAttributes.Virtual, method.ReturnType, paramTypes);
// define method attribute if exists
SWCommandAttribute CommandMethodAttr = (SWCommandAttribute)Attribute.GetCustomAttribute(method, typeof(SWCommandAttribute));
if (CommandMethodAttr != null)
{
methodBody.SetCustomAttribute(SWCommandAttribute.GetCustomAttributeBuilder(CommandMethodAttr));
}
// define method parameters with their attributes
for (int i = 0; i < paramCount; ++i)
{
ParameterBuilder param = methodBody.DefineParameter(i + 1, paramAttrs[i], paramNames[i]);
SWParameterAttribute[] ParameterAttr = (SWParameterAttribute[])prms[i].GetCustomAttributes(typeof(SWParameterAttribute), false);
if (ParameterAttr.Length > 0)
{
param.SetCustomAttribute(SWParameterAttribute.GetCustomAttributeBuilder(ParameterAttr[0]));
}
}
// generate method body
GenerateMethodBody(methodBody.GetILGenerator(), RetType, prms);
}
/// <summary>
/// An attribute builder method
/// </summary>
/// <param name="attr"></param>
/// <returns></returns>
public static CustomAttributeBuilder GetCustomAttributeBuilder(SWCommandAttribute attr)
{
string commandText = attr.m_commandText;
object returnIfNull = attr.m_returnIfNull;
if(returnIfNull == null) returnIfNull = NullReturnValueToken;
Type[] arrParamTypes = new Type[] {typeof(SWCommandType), typeof(string), typeof(object), typeof(MissingSchemaAction)};
object[] arrParamValues = new object[] {attr.m_commandType, commandText, returnIfNull, attr.m_missingSchemaAction};
ConstructorInfo ctor = typeof(SWCommandAttribute).GetConstructor(arrParamTypes);
return new CustomAttributeBuilder(ctor, arrParamValues);
}
/// <summary>
/// Executes Sql command and returns execution result.
/// Command text, type and parameters are taken from method using reflection.
/// Command parameter values are taken from method parameter values.
/// </summary>
/// <param name="connection">Connection property.</param>
/// <param name="transaction">Transaction property.</param>
/// <param name="method"><see cref="MethodInfo"/> type object from which the command object is built.</param>
/// <param name="values">Array of values for the command parameters.</param>
/// <param name="autoCloseConnection">Determines if the connection must be closed after the command execution.</param>
/// <returns></returns>
public static object ExecuteMethodAndGetResult(DbConnection connection, DbTransaction transaction, MethodInfo method, object[] values, bool autoCloseConnection)
{
if (method == null)
{
// this is done because this method can be called explicitly from code.
method = (MethodInfo)(new StackTrace().GetFrame(1).GetMethod());
}
// create command object
DatabaseHelper db = new DatabaseHelper();
DbCommand command = db.Command;
command.Connection = connection;
command.Transaction = transaction;
// define default command properties (command text, command type and missing schema action)
string commandText = method.Name;
SWCommandType swCommandType = SWCommandType.StoredProcedure;
MissingSchemaAction missingSchemaAction = MissingSchemaAction.Add;
// try to get command properties from calling method attribute
SWCommandAttribute commandAttribute = (SWCommandAttribute)Attribute.GetCustomAttribute(method, typeof(SWCommandAttribute));
if (commandAttribute != null)
{
if (commandAttribute.CommandText.Length > 0)
{
commandText = commandAttribute.CommandText;
}
swCommandType = commandAttribute.CommandType;
missingSchemaAction = commandAttribute.MissingSchemaAction;
}
// set command text
command.CommandText = commandText;
// set command type
switch (swCommandType)
{
case SWCommandType.InsertUpdate: command.CommandType = CommandType.Text; break;
case SWCommandType.StoredProcedure: command.CommandType = CommandType.StoredProcedure; break;
case SWCommandType.Text: command.CommandType = CommandType.Text; break;
default: command.CommandType = CommandType.Text; break;
}
// define command parameters.
// In this step command text can be changed.
int[] indexes = new int[values.Length];
GenerateCommandParameters(command, method, values, indexes, swCommandType);
// execute command
object result = null;
result = ExecuteCommand(command, method.ReturnType, autoCloseConnection, missingSchemaAction);
// return command parameter values
for (int i = 0; i < values.Length; ++i)
{
int sqlParamIndex = indexes[i];
if (sqlParamIndex >= 0)
{
values[i] = command.Parameters[i].Value;
}
}
// adjust null result
if (result == null || result == System.DBNull.Value)
{
if (commandAttribute != null)
{
result = commandAttribute.ReturnIfNull;
if (method.ReturnType == typeof(DateTime))
{
result = new DateTime((int)commandAttribute.ReturnIfNull);
}
}
}
return(result);
}
