不支持“等于”方法

问题描述：

public List<Health_Scheme_System.Employee> GetPenEmployeeTable() 
{ 
    Health_Scheme_System.Health_Scheme_SystemDB db = new Health_Scheme_System.Health_Scheme_SystemDB(); 

    var x = (from c in db.Employees 
      where c.Pensioners.Equals (1) 
      select c); 

    return x.ToList(); 
} 

//Selecting multiple columns from an HR view table together with the scheme name of scheme. 
public List<EmployeesX> GetPensioners() 
{ 
    Health_Scheme_System.Health_Scheme_SystemDB db = new Health_Scheme_System.Health_Scheme_SystemDB(); 

    List<Health_Scheme_System.EmployeeDirectory> listEmployeeView = GetPenEmployeeView(); 
    List<Health_Scheme_System.Employee> listEmployeeTable = GetPenEmployeeTable(); 
    List<Health_Scheme_System.Scheme> listSchemes = GetSchemes(); 

    List<EmployeesX> listOfEmployees = new List<EmployeesX>(); 

    //checking for comparision of getemployeeview to getemployee table and then to getschemes 
    //Then display the scheme name if they are similar. 
    for (int i = 0; i < listEmployeeView.Count; i++) 
    { 
     EmployeesX emp = new EmployeesX(); 
     emp.ID_NO = listEmployeeView[i].ID_NO; 
     emp.FIRST_NAME = listEmployeeView[i].FIRST_NAME; 
     emp.LAST_NAME = listEmployeeView[i].LAST_NAME; 
     emp.LOCATION_CODE = listEmployeeView[i].LOCATION_CODE; 

     for (int j = 0; j < listEmployeeTable.Count; j++) 
     { 
      if (listEmployeeTable[j].EmployeeIDCard == listEmployeeView[i].ID_NO) 
      { 
       emp.Pensioners = listEmployeeTable[j].Pensioners; 

        for (int k = 0; k < listSchemes.Count; k++) 
        { 
         if (listEmployeeTable[j].SchemeID == listSchemes[k].SchemeID) 
         { 
          emp.SCHEME_NAME = listSchemes[k].Name; 
          emp.START_DATE = listEmployeeTable[j].StartSchemeDate; 
         } 
        } 
      } 
     } 
     listOfEmployees.Add(emp); 
    } 
    return listOfEmployees; 
}

如何使用.equals？不支持“等于”方法

答

你有没有尝试过这样的：

var x = (from c in db.Employees 
     where c.Pensioners == 1 
     select c)

附加信息：

如果在LINQ查询使用方法的对象上亚音速需要知道如何翻译成PUR SQL代码。这在默认情况下不起作用，并且必须针对每个数据提供者的每种受支持类型上的每个已知方法实施（如果与默认实现不同）。所以对亚音速有很多工作要做。

了解什么是支持的，什么不是TSqlFormatter类的一个很好的起点。看看protected override Expression VisitMethodCall(MethodCallExpression m)

https://github.com/subsonic/SubSonic-3.0/blob/master/SubSonic.Core/Linq/Structure/TSqlFormatter.cs

已经有一个Equals

 else if (m.Method.Name == "Equals") 
     { 
      if (m.Method.IsStatic && m.Method.DeclaringType == typeof(object)) 
      { 
       sb.Append("("); 
       this.Visit(m.Arguments[0]); 
       sb.Append(" = "); 
       this.Visit(m.Arguments[1]); 
       sb.Append(")"); 
       return m; 
      } 
      else if (!m.Method.IsStatic && m.Arguments.Count == 1 && m.Arguments[0].Type == m.Object.Type) 
      { 
       sb.Append("("); 
       this.Visit(m.Object); 
       sb.Append(" = "); 
       this.Visit(m.Arguments[0]); 
       sb.Append(")"); 
       return m; 
      } 
      else if (m.Method.IsStatic && m.Method.DeclaringType == typeof(string)) 
      { 
       //Note: Not sure if this is best solution for fixing side issue with Issue #66 
       sb.Append("("); 
       this.Visit(m.Arguments[0]); 
       sb.Append(" = "); 
       this.Visit(m.Arguments[1]); 
       sb.Append(")"); 
       return m; 
      } 
     }

的实现，我想Prnsioners是一个整数类型，所以你基本上得再添否则，如果和recomplie亚音速。

这应该工作，但我没有测试过它。

  else if (!m.Method.IsStatic && m.Method.DeclaringType == typeof(int)) 
      { 
       sb.Append("("); 
       this.Visit(m.Arguments[0]); 
       sb.Append(" = "); 
       this.Visit(m.Arguments[1]); 
       sb.Append(")"); 
       return m; 
      }

（或者您可以尝试==方法，如顶部的示例中所示）。

不支持“等于”方法

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