public static DynamicBuilder <T> CreateBuilder(IDataRecord dr)
{
DynamicBuilder <T> dynamicBuilder = new DynamicBuilder <T>();
dynamicBuilder.handler = (Load)MyStagingUtils.CreateDynamicDelegate(typeof(T), dr, typeof(Load));
return(dynamicBuilder);
}
/// <summary>
/// 创建动态执行代码
/// </summary>
/// <param name="dataRecord"></param>
/// <returns></returns>
public static DynamicBuilder <T> CreateBuilder(IDataRecord dataRecord)
{
DynamicBuilder <T> dynamicBuilder = new DynamicBuilder <T>();
DynamicMethod method = new DynamicMethod("DynamicCreate", typeof(T),
new Type[] { typeof(IDataRecord) }, typeof(T), true);
ILGenerator generator = method.GetILGenerator();
LocalBuilder result = generator.DeclareLocal(typeof(T));
generator.Emit(OpCodes.Newobj, typeof(T).GetConstructor(Type.EmptyTypes));
generator.Emit(OpCodes.Stloc, result);
PropertyInfo[] pis = typeof(T).GetProperties();
IDictionary <string, PropertyInfo> drNameList = new Dictionary <string, PropertyInfo>();
for (int i = 0; i < pis.Length; i++)
{
PropertyInfo pi = pis[i];
drNameList[pi.Name.ToLower()] = pi;
}
for (int i = 0; i < dataRecord.FieldCount; i++)
{
string fieldName = dataRecord.GetName(i).ToLower();
if (drNameList.ContainsKey(fieldName) == false)
{
continue;
}
PropertyInfo propertyInfo = drNameList[fieldName];
Label endIfLabel = generator.DefineLabel();
if (propertyInfo != null && propertyInfo.GetSetMethod() != null)
{
generator.Emit(OpCodes.Ldarg_0);
generator.Emit(OpCodes.Ldc_I4, i);
generator.Emit(OpCodes.Callvirt, isDBNullMethod);
generator.Emit(OpCodes.Brtrue, endIfLabel);
generator.Emit(OpCodes.Ldloc, result);
generator.Emit(OpCodes.Ldarg_0);
generator.Emit(OpCodes.Ldc_I4, i);
generator.Emit(OpCodes.Callvirt, getValueMethod);
Type memberType = propertyInfo.PropertyType;
Type nullUnderlyingType = Nullable.GetUnderlyingType(memberType);
Type unboxType = nullUnderlyingType != null ? nullUnderlyingType : memberType;
bool isEnum = unboxType.GetTypeInfo().IsEnum;
if (unboxType == typeof(byte[]) || unboxType == typeof(string))
{
generator.Emit(OpCodes.Castclass, memberType);
}
else if (isEnum)
{
generator.Emit(OpCodes.Unbox_Any, memberType);
}
else if (unboxType == typeof(char))
{
generator.Emit(OpCodes.Call, typeof(Convert).GetMethod("ToChar", new Type[] { typeof(object) }));
}
else if (unboxType == typeof(JToken))
{
generator.Emit(OpCodes.Call, typeof(JToken).GetMethod("Parse", new Type[] { typeof(string) }));
}
else
{
generator.Emit(OpCodes.Unbox_Any, dataRecord.GetFieldType(i));
if (nullUnderlyingType != null)
{
generator.Emit(OpCodes.Newobj, memberType.GetConstructor(new[] { nullUnderlyingType }));
}
}
generator.Emit(OpCodes.Callvirt, propertyInfo.GetSetMethod());
generator.MarkLabel(endIfLabel);
}
}
generator.Emit(OpCodes.Ldloc, result);
generator.Emit(OpCodes.Ret);
dynamicBuilder.handler = (Load)method.CreateDelegate(typeof(Load));
return(dynamicBuilder);
}
