如何設置動態凡在LINQ查詢條款與C＃

Question

我有這樣的代碼： -

DataSet ds = new DataSet(); 

String s = "StudentID = 5 Or StudentID=6"; 
var result = from r in ds.table[0].AsEnumerable() where s.ToString() select r; 

如何從這個獲取數據？

Answer 1

試試這個

var result = ds.Tables[0].AsEnumerable().Where(row => row["StudentID"].ToString() == "5" || row["StudentID"].ToString() == "6") 

或

var result = from r in dx.AsEnumerable() 
      where r["StudentID"].ToString() == "5" || r["StudentID"].ToString() == "6" 
      select r; 

你可以試試這個

DataTable dt = result.CopyToDataTable(); //for both code above 

Answer 2

爲什麼你不能使用的ID列表？

//assuming you have text and that's the reason 
var txtIDs = "5,6"; 
var IDs = txtIDs.Split(',').Select(s => int.Parse(s)); 

var rows = from r in ds.Tables[0].AsEnumerable() 
      where IDs.Any(id => r.Field<int>("ID")==id) 
      select r; 

或方法的語法：

var rows = ds.Tables[0].AsEnumerable() 
      .Where(r => IDs.Contains(r.Field<int>("ID")));