如何使用LINQ過濾DataTable

Question

我有DataTable，它使我從數據庫中獲取數據。

• Name
• Address
• CountryID

我想通過LINQ過濾我這邊的數據：我有與ID爲1，2，3，4個國家複選框列表我只想得到被檢查國家的結果。例如1，2，4爲LINQ的CountryID。我想將它綁定到網格視圖。

我使用下面的代碼：

foreach (ListItem cBox in chkGodownlst.Items) 
{ 
    if (cBox.Selected) 
    { 
     var a = dt.AsEnumerable() 
        .Where(r => r.Field<int>("CountryID") == Convert.ToInt32(cBox.Value)); 
    } 
} 

Answer 1

嘗試這樣：

// Get all checked id's. 
var ids = chkGodownlst.Items.OfType<ListItem>() 
    .Where(cBox => cBox.Selected) 
    .Select(cBox => cBox.Value) 
    .ToList(); 

// Now get all the rows that has a CountryID in the selected id's list. 
var a = dt.AsEnumerable().Where(r => 
    ids.Any(id => id == r.Field<int>("CountryID")) 
); 

// Create a new table. 
DataTable newTable = a.CopyToDataTable(); 

// Now set the new table as DataSource to the GridView. 

Answer 2

你應該試試這個：

var collection = new List<dynamic>(); 
foreach (ListItem cBox in chkGodownlst.Items) 
{ 
    if(cBox.Selected) 
    { 
     collection.AddRange(dt.AsEnumerable().Where(r => r.Field<int>("CountryID") == Convert.ToInt32(cBox.Value))); 
    } 
} 

GridView1.DataSource = collection; 
GridView1.DataBind(); 

希望這將幫助！