hotline/src/Hotline/Tools/DynamicClassHelper.cs

using System.Reflection;
using System.Reflection.Emit;
using Hotline.Share.Dtos;
using Hotline.Share.Dtos.Order;
using MiniExcelLibs.Attributes;
using XF.Domain.Extensions;

namespace Hotline.Tools;

public class DynamicClassHelper
{
    public static Type CreateDynamicClass(List<ColumnInfo> propInfos)
    {
        string className = "DynamicClass";
        AssemblyName assemblyName = new AssemblyName("DynamicAssembly");
        AssemblyBuilder assemblyBuilder = AssemblyBuilder.DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.Run);
        ModuleBuilder moduleBuilder = assemblyBuilder.DefineDynamicModule("MainModule");
        TypeBuilder typeBuilder = moduleBuilder.DefineType(className, TypeAttributes.Public);

        foreach (var property in propInfos)
        {
            var propertyName = property.Prop.Trim().ToPascalCase();
            var propertyType = typeof(string);

            FieldBuilder fieldBuilder = typeBuilder.DefineField("_" + propertyName, propertyType, FieldAttributes.Private);
            PropertyBuilder propertyBuilder = typeBuilder.DefineProperty(propertyName, PropertyAttributes.HasDefault, propertyType, null);

            MethodAttributes getSetAttributes = MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.HideBySig;

            MethodBuilder getMethodBuilder = typeBuilder.DefineMethod("get_" + propertyName, getSetAttributes, propertyType, Type.EmptyTypes);
            ILGenerator getIL = getMethodBuilder.GetILGenerator();
            getIL.Emit(OpCodes.Ldarg_0);
            getIL.Emit(OpCodes.Ldfld, fieldBuilder);
            getIL.Emit(OpCodes.Ret);

            MethodBuilder setMethodBuilder = typeBuilder.DefineMethod("set_" + propertyName, getSetAttributes, null, new Type[] { propertyType });
            ILGenerator setIL = setMethodBuilder.GetILGenerator();
            setIL.Emit(OpCodes.Ldarg_0);
            setIL.Emit(OpCodes.Ldarg_1);
            setIL.Emit(OpCodes.Stfld, fieldBuilder);
            setIL.Emit(OpCodes.Ret);

            propertyBuilder.SetGetMethod(getMethodBuilder);
            propertyBuilder.SetSetMethod(setMethodBuilder);

            var columnNameCtorInfo = typeof(ExcelColumnNameAttribute).GetConstructor(new Type[] { typeof(string), typeof(string[]) });
            var attributeBuilder = new CustomAttributeBuilder(columnNameCtorInfo, new object[] { property.Name, null });
            propertyBuilder.SetCustomAttribute(attributeBuilder);
        }

        Type generatedType = typeBuilder.CreateType();
        return generatedType;
    }
}