Question

我是Silverlight MVVM的新手，我正在创建一个项目，我将数据绑定到DataGrid。

这是我的数据库结构：

tblAuthorizationVarification （AuthorizationVarificationid，AuthorizationRequestid，number）
tblAuthorizationRequest（AuthorizationRequestid，name）
tblAuthorizationVarificationDetails（DetailId，AuthorizationRequestid，Amount）

我想在gridview中显示所有授权的总金额。

以下是我的代码，在ViewModel课程中，我从tblAuthorizationRequest获得tblAuthorizationVarification：

PagedCollectionView _AuthorizationVarificationList;

public PagedCollectionView AuthorizationVarificationList
{
  get { return _AuthorizationVarificationList; }
  set 
  {
     _AuthorizationVarificationList = value;
     OnPropertyChanged("AuthorizationVarificationList"); }
  }

  private void GetVarifications()
  {
    IsBusy = true;
    LoadOperation<AuthorizationVerification> loadOp = 
                          objContext.Load(objContext.GetCreditNotesQuery());

    loadOp.Completed += (sender, e) =>
    {
       IEnumerable<AuthorizationVerification> op = 
               ((LoadOperation<AuthorizationVerification>)sender).Entities;
       PagedCollectionView view = new PagedCollectionView(op);
       this.AuthorizationVarificationList = view;
       cnt = cnt - 1;
       if (cnt <= 0)
         IsBusy = false;
    };
  }

AuthorizationVarificationList在Gridview中绑定就像

一样

<sdk:DataGrid x:Name="grdCreditNotes" 
    ItemsSource="{Binding Path=AuthorizationVarificationList}" 
    SelectedItem="{Binding Path=SelectedCreditNote, Mode=TwoWay}" 
    AutoGenerateColumns="False" IsReadOnly="True" Grid.Row="2" 
    VerticalAlignment="Stretch" Margin="0,0,0,0">

    <sdk:DataGrid.Columns>
      <sdk:DataGridTextColumn Header="Credit No" 
         Binding="{Binding Path=AuthorizationVerificationId}" Width="200"/>

      <sdk:DataGridTextColumn Header="Amount" 
         Binding="{Binding Path=AuthorizationRequest.Amount}" MinWidth="100" 
         Width="*"/>

    </sdk:DataGrid.Columns>    
</sdk:DataGrid>

对于这个网格领域的特定授权量的显示和，能做什么？

Answer 1

正如我已经建议的那样，您可以为集合项创建一个视图模型类，并按原样填充它。

public class VerificationViewModel
{
    public int AuthorizationVerificationId { get; set; }

    public double Amount { get; set; }
}

然后使用LINQ查询对集合进行分组并返回汇总项：

loadOp.Completed += (sender, e) =>
{
   IEnumerable<AuthorizationVerification> op = 
           ((LoadOperation<AuthorizationVerification>)sender).Entities;

   var models = op.GroupBy(item => item.AuthorizationVerificationId)
                  .Select(g => new VerificationViewModel
                                { 
                                    AuthorizationVerificationId = g.Key, 
                                    Amount = g.Sum(gi => gi.Amount) 
                                })
                  .ToList();

   PagedCollectionView view = new PagedCollectionView(models);
   // Everything else is the same
}

//Also change the type of the property which is bound to SelectedItem
public VerificationViewModel SelectedCreditNote { get; set; }

并更改第二列的绑定路径：

<sdk:DataGrid.Columns>
  <sdk:DataGridTextColumn Header="Credit No" 
     Binding="{Binding Path=AuthorizationVerificationId}" Width="200"/>

  <sdk:DataGridTextColumn Header="Amount" 
     Binding="{Binding Path=Amount}" MinWidth="100" Width="*"/>

</sdk:DataGrid.Columns>

此代码应计算每个Id的金额总和。如果您想要其他聚合，可以更改linq查询。

Answer 2

如果我理解正确你是在摘要行之后？如果是，请查看以下链接http://leeontech.wordpress.com/2010/02/01/summary-row-in-datagrid/。您可能需要更好地塑造ViewModel后面的Model对象（将模型（在这种情况下为DTO）直接显示给View是很好的做法。）

使用MVVM中的计算绑定DataGridTextColumn

2 个答案: