Question

datagrid在foreach循环中没有更新。在下面的代码中，一旦线程完成但数据网格之间没有更新。因为我的foreach循环是另一个类。我知道我必须以某种方式实现BackgroundWorker.OnProgressChanged方法来更新进度但无法弄清楚。

XMAL FILE

<dg:DataGrid ItemsSource="{Binding}">
                    <dg:DataGrid.Columns>
                    <dg:DataGridTextColumn Binding="{Binding grade, Mode=TwoWay, IsAsync=True}" Header="Status"/>
                    </dg:DataGrid.Columns>
                </dg:DataGrid>

GUI CLASS

public partial class GUIClass : Page
            {
                 BackgroundWorker bgWorker = new BackgroundWorker();
                 public GUIClass ()
                 {
                    InitializeComponent();
                    bgWorker.WorkerSupportsCancellation = true;
                    bgWorker.WorkerReportsProgress = true;
                 }

                 private void btnOK_Click(object sender, RoutedEventArgs e)
                {  
                     bgWorker.DoWork += new DoWorkEventHandler(bgWorker_DoWork);
                    bgWorker.ProgressChanged += new ProgressChangedEventHandler(bgWorker_ProgressChanged);
                    bgWorker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgWorker_RunWorkerCompleted);
                    bgWorker.RunWorkerAsync();
                }

                void bgWorker_DoWork(object sender, DoWorkEventArgs e)
                {
                    ClassA cls= new ClassA();
                    cls.runprocess();
                }

             void bgWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
             {
                    dataGrid1.Items.Refresh();
             }

             void bgWorker_RunWorkerCompleted(object sender,RunWorkerCompletedEventArgs e)
              {
                   ....
                  .....
                  dataGrid1.Items.Refresh();
              }

    }

DataGrid绑定类

public class BindClass
{
        public bool staus{ set; get; }
        public string grade{ set; get; }
}

ClassA

class ClassA
{
    public void runprocess()
    {
          foreach (var item in IEnumerable<BindClass> )
          {
             if(somecondition)
             {
                  // I want to update datagrid at this stage so user can see it
                   item.grade="First"
             }  
          }
    }
}

Answer 1

为了在更改类的“grade”属性时更新datagrid，需要实现INotifyPropertyChanged。尝试更新您的课程如下：

public class BindClass : INotifyPropertyChanged
{
 private string _grade;

 public string Grade
 {
   get { return _grade; }
   set
   {
     if (_grade == value)
       return;

     _grade = value;
     OnPropertyChanged("Grade");
   }
 }

 public event PropertyChangedEventHandler PropertyChanged;

 protected void OnPropertyChanged(string property)
 {
   if (PropertyChanged!=null)
   {
     PropertyChanged(this, new PropertyChangedEventArgs(property));
   }
 }
}

注意 - 我已将属性名称从“grade”更改为“Grade”以遵循.NET约定。我相信你可以自己添加status属性的实现; - ）

Answer 2

我会寻求一个解决方案，其中dataGrid的ItemsSource是ObservableCollection，使事情变得更容易，而且我认为你可以根据你所写的内容做到这一点。

像这样你不必去实现INotifyPropertyChanged事件处理程序的麻烦

（注意：ObservableCollections修改更新UI，而其他Collection类型则不更新）。这就是MS建议在dataGrid的doc中做的事情（尽管我不能把我的手放在我读过的那些文档上）

使用backgroundworker更新datagrid WPF

2 个答案: