C#根据前台传入实体名称实现动态查询数据

var entityType=Assembly.Load("XXX.Entity").GetTypes().Any(a =>a.Name == entityName).FirstOrDefault().FullName;

var name = DBContext.Model.GetEntityTypes().Where(a => a.ClrType.Name == "传入的实体名称").Select(a => a.ClrType.Namespace).FirstOrDefault();

var assemblyName = AppDomain.CurrentDomain.GetAssemblies().Where(a => a.FullName.Contains(name)).Select(a => a.FullName).FirstOrDefault();

var entityType = Assembly.Load(assemblyName).GetTypes().Where(a => a.Name == "传入的实体名称").FirstOrDefault();

var repositoryType = typeof(Repository<>).MakeGenericType(entityType);//Repository<> 一般项目会封装仓储层放一些CRUD的公共方法
var repository = Activator.CreateInstance(repositoryType, DBContext);
var queryMethod = repositoryType.GetMethod("GetList"); //这里写需要调用的方法名称

var parameterExpression=Expression.Parameter(entityType,"x");
var propertyExpression = Expression.Property(parameterExpression, "字段名称");
var constantExpression = Expression.Constant(ConvertFieldValue("字段的值", propertyExpression.Type));
var equalExpression = Expression.Equal(propertyExpression,constantExpression);
var lambdaExpression = Expression.Lambda(equalExpression, parameterExpression);

private object ConvertFieldValue(string fieldValue, Type type)
{
 		    if (type == typeof(DateTime))
           {
               return DateTime.ParseExact(fieldValue, "dd/MM/yyyy HH:mm:ss",CultureInfo.InvariantCulture);
           }
           else if (type == typeof(bool))
           {
               return Convert.ToBoolean(fieldValue);
           }
           else if (type == typeof(int))
           {
               return Convert.ToInt32(fieldValue);
           }
           else if (type == typeof(long))
           {
               return Convert.ToInt64(fieldValue);
           }
           else
           {
               return fieldValue;
           }
}

//获取参数列表
var parameters = queryMethod.GetParameters();
var arguments = new List<object>();
for (int i = 0; i < parameters.Length; i++)
{
   if (i == 0)
   {
      //如果不需要根据条件查询可以直接设置为默认值
      arguments.Add(lambdaExpression); 
   }
   else
   {
      //设置其他参数为默认值
      arguments.Add(Missing.Value);
   }
}

var list = queryMethod.Invoke(repository, arguments.ToArray());