Question

Im trying to change a property value (using reflection) that matches with the column name of the datatable that im looping.

Here is my code for change the property:

Type type = myTypeBuilder.CreateType();
foreach (DataRow row in table.Rows)
{
 object testobject = Activator.CreateInstance(retval, true);
 foreach (DataColumn col in table.Columns)
 {
   PropertyInfo property = testobject .GetType().GetProperty(col.ColumnName);
   property.SetValue(testobject , row[col], BindingFlags.CreateInstance, null, null, null);
 }
}

As result, im getting the right property while im looping through DataColumns of the table, but after the SetValue all the properties values of my “testobject” are set with the value that only the selected property should have.

This is the way i generate the Type:

foreach (DataColumn col in table.Columns)
        {
            string propertyname=col.ColumnName;
            // The last argument of DefineProperty is null, because the 
            // property has no parameters. (If you don't specify null, you must 
            // specify an array of Type objects. For a parameterless property, 
            // use an array with no elements: new Type[] {})

            PropertyBuilder custNamePropBldr = myTypeBuilder.DefineProperty(propertyname, System.Reflection.PropertyAttributes.None, typeof(string), null);
            // The property set and property get methods require a special 
            // set of attributes.
            MethodAttributes getSetAttr = MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.HideBySig;

            // Define the "get" accessor method for CustomerName.
            MethodBuilder custNameGetPropMthdBldr = myTypeBuilder.DefineMethod("get_"+propertyname, getSetAttr, typeof(string), Type.EmptyTypes);

            ILGenerator custNameGetIL = custNameGetPropMthdBldr.GetILGenerator();
            custNameGetIL.Emit(OpCodes.Ldarg_0);
            custNameGetIL.Emit(OpCodes.Ldfld, customerNameBldr);
            custNameGetIL.Emit(OpCodes.Ret);

            // Define the "set" accessor method for CustomerName.
            MethodBuilder custNameSetPropMthdBldr = myTypeBuilder.DefineMethod("set_"+propertyname, getSetAttr, null, new Type[] { typeof(string) });

            ILGenerator custNameSetIL = custNameSetPropMthdBldr.GetILGenerator();
            custNameSetIL.Emit(OpCodes.Ldarg_0);
            custNameSetIL.Emit(OpCodes.Ldarg_1);
            custNameSetIL.Emit(OpCodes.Stfld, customerNameBldr);
            custNameSetIL.Emit(OpCodes.Ret);

            // Last, we must map the two methods created above to our PropertyBuilder to  
            // their corresponding behaviors, "get" and "set" respectively. 
            custNamePropBldr.SetGetMethod(custNameGetPropMthdBldr);
            custNamePropBldr.SetSetMethod(custNameSetPropMthdBldr);
        }

Do you know what could be the cause?

Thanks

Jose.

Answer 1

Seems that your customerNameBldr is never changed in foreach loop (when you generate the type).

This way all property setters and getters reference the same field thus all setters will change value of the same field and all property getters will get value of the same field.

custNameGetIL.Emit(OpCodes.Ldfld, customerNameBldr);