ExecuteStoreQuery EntityFramework

Question

params新手object[]...and想尝试Returning a DataTable using Entity Framework ExecuteStoreQuery的建议

如何使用实体框架将这些参数(guid gId, string sName)传递给存储过程？这就是我想要尝试的，因为我需要返回一个数据表。

public DataTable ExecuteStoreQuery(string commandText, params Object[] parameters)
{
   DataTable retVal = new DataTable();
   retVal = context.ExecuteStoreQuery<DataTable>(commandText, parameters).FirstOrDefault();    
   return retVal;
}

Answer 1

正如您所链接的问题/答案所告诉您的，ExecuteStoreQuery返回实体-它不能返回DataTable。

您可以使用它返回一个实体集合，然后使用DataTableExtensions将其转换为DataTable

public DataTable ExecuteStoreQuery(string commandText, params Object[] parameters)
{
   DataTable retVal;

   var entities = context.ExecuteStoreQuery<MyEntity>(commandText, parameters)
                          .Take(1); // use `Take` instead of `First` to keep it as a collection
   retVal = entities.AsEnumerable().CopyToDataTable();
   return retVal;
}

就params而言，它只允许在方法调用中将值串在一起，而不是将它们打包在object[]中

DataTable dt = ExecuteStoreQuery("SELECT * FROM...", guid, sName);

Answer 2

The idea of params (which always has to be the last decalared parameter in a function can be unlimited for example

Function Foo(string s,params Object[] alist)
{
    //whatever
}

Cats cat = new Cats();//I put an object here because cat is an object, if it was ints they would all have to be ints
Foo("ok",cat);
Foo("ok", cat,cat,cat,cat,cat,cat);

are both valid

是这样的，但是您想要传递SQL参数，所以...

            dt = ExecuteStoreQuery("INSERT INTO STATUS(ITEMTYPE,PRODESC) values(@ITEMTYPE,'@PRODESC')",new SqlParameter("@ITEMTYPE", 2),new SqlParameter("@PRODESC", "Obama sucks"));

或者更多的眼线，这样我就能看得更清楚

        object[] obj;
        obj[0] = new SqlParameter("@ITEMTYPE", 2);
        obj[1] = new SqlParameter("@PRODESC", "Obama sucks");
        dt = ExecuteStoreQuery("INSERT INTO STATUS(ITEMTYPE,PRODESC) values(@ITEMTYPE,'@PRODESC')",obj);