填充DataGridView之后，应用程序挂起 [英] Application Hangs after a DataGridView is Populated

问题描述

我有一个带有两个按钮(开始"和停止")和一个DataGridView(名为Grid)的简单表单.我正在尝试使用WMI查询的结果填充DataGridView，该WMI查询枚举Win32_Process实例，并将所有进程名称放在DataGridView的唯一列中.代码如下所示:

I have a simple form with two buttons (Start and Stop) and a DataGridView (named Grid). I am trying to populate the DataGridView with the results of a WMI query that enumerates Win32_Process instances and puts all process names in the only column of the DataGridView. The code looks like this:

using System;
using System.Management;
using System.Windows.Forms;

namespace WindowsFormsApplication10
{
    public partial class Form1 : Form
    {
        ManagementObjectSearcher Searcher =
            new ManagementObjectSearcher();

        SelectQuery Query = new SelectQuery();
        
        ManagementOperationObserver Observer =
            new ManagementOperationObserver();
        
        public Form1()
        {
            InitializeComponent();
            
            Observer.Completed +=
                new CompletedEventHandler(Observer_Completed);
            Observer.ObjectReady +=
                new ObjectReadyEventHandler(Observer_ObjectReady);
            Grid.ColumnCount = 1;
            Grid.Columns[0].Name = "Name";
        }

        private void Start_Click(object sender, EventArgs e)
        {
            Query.QueryString = "Select * From Win32_Process";
            Searcher.Query = Query;

            Searcher.Get(Observer);
        }

        private void Observer_Completed
            (object sender, CompletedEventArgs e)
        {
            Grid.Refresh();
        }

        private void Observer_ObjectReady
            (object sender, ObjectReadyEventArgs e)
        {
            string [] row = new string [] 
                {e.NewObject["Name"].ToString()};
            Grid.Rows.Add(row);

            Grid.Refresh();
        }

        private void stop_Click(object sender, EventArgs e)
        {
            Observer.Cancel();
        }
    }
}

当我使用开始调试"选项运行代码时，它运行良好并填充了DataGridView.我注意到的一件奇怪的事情(至少对我而言)是，在Observer_ObjectReady中，从未达到Grid.Refresh()行.当我使用不调试开始"运行代码时，将填充DataGridView，但此后窗体立即冻结.我该如何处理? (很抱歉，如果这还不够，我愿意在必要时提供更多信息，但是，正如您可能已经注意到的那样，我对C#或Visual Studio没有太多的经验.)

我已经能够使用相同的异步代码并将数据发送到RichTextBox，但我也希望能够填充DataGridView.我想这与DataGridView有关，但是我感到困惑，因为我没有得到任何异常，应用程序冻结了，而当我用RichTextBox替换DataGridView并从Observer_ObjectReady添加文本行时，同一个应用程序运行良好.

(我在StackOverflow上发布了相同的问题，但没有解决方法)

When I run the code using the ''Start Debugging'' option it runs fine and populates the DataGridView. One strange thing (at least to me) I noticed is that in the Observer_ObjectReady the Grid.Refresh() line is never reached. When I run the code with ''Start Without Debugging'' the DataGridView is populated but the form freezes immediately after that. How can I deal with this? (Sorry if this is not enough information - I am willing to provide more if necessary, but, as you might have noticed, I don''t have much experience with C# or Visual Studio).

I have been able to use the same asynchronous code and send the data to a RichTextBox, but I would also like to be able to populate a DataGridView. I suppose this has to do with a DataGridView, but I am puzzled because I don''t get any exceptions, the application just freezes, while the same application works fine when I replace the DataGridView with a RichTextBox and add lines of text from Observer_ObjectReady.

(I have posted the same question on StackOverflow, but without a resolution)

推荐答案

如果没有尝试过，我就可以肯定它是线程问题.除了GUI线程(创建相应窗口句柄的线程)外，不允许将GUI元素更改为其他任何元素.
看看 Control.Invoke [

Hi,

without having tried it I''m relatively sure that its a threading issue. GUI elements are not allowed to be changed from any other than the GUI thread (the thread which created the corresponding window handle).
Have a look at Control.Invoke[^].

So why does it work with the RichtTextBox? I don''t know. The behaviour is nearly random when doing inter-thread-calls with GUI elements.

Robert

您是对的，我已经能够使用Control.BeginInvoke使它正常工作.谢谢您的回答.

You are right, and I have been able to make it work using Control.BeginInvoke. Thank you for the answer.

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