错误:在创建窗口句柄之前，不能对控件调用Invoke或BeginInvoke
本文关键字：控件 调用 Invoke BeginInvoke 不能 创建 窗口句柄 错误 | 更新日期: 2023-09-27 18:24:04
首先，让我说我已经讨论这个问题将近两天了：尝试了各种替代方案，并从您的网站上阅读了大量有类似问题的问题。
首先让我粘贴我的代码，这样你就可以得到整个画面。
编辑：根据论坛成员的请求，删除了一些可能对问题不必要的代码。
表格1.cs
namespace TestApp
{
public partial class Form1 : Form
{
//global declarations
private static Form1 myForm;
public static Form1 MyForm
{
get
{
return myForm;
}
}
List<DataSet> DataSets = new List<DataSet>();
int typeOfDataset = 0;
//delegate for background thread to communicate with the UI thread _
//and update the metadata autodetection progress bar
public delegate void UpdateProgressBar(int updateProgress);
public UpdateProgressBar myDelegate;
//***************************
//**** Form Events ********
//***************************
public Form1()
{
InitializeComponent();
if (myForm == null)
{
myForm = this;
}
DataSets.Add(new DSVDataSet());
DataSets[typeOfDataset].BWorker = new BackgroundWorker();
DataSets[typeOfDataset].BWorker.WorkerSupportsCancellation = true;
myDelegate = new UpdateProgressBar(UpdateProgressBarMethod);
}
private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
//e.Cancel = true;
if (DataSets[typeOfDataset].BWorker != null || DataSets[typeOfDataset].BWorker.IsBusy)
{
Thread.Sleep(1000);
DataSets[typeOfDataset].BWorker.CancelAsync();
}
Application.Exit();
}
//***************************
//*** Menu Items Events ***
//***************************
private void cSVToolStripMenuItem_Click(object sender, EventArgs e)
{
LoadFillDSVData(',');
}
//***************************
//*** DataGridViews Events **
//***************************
private void dataGridView1_RowPostPaint(object sender, DataGridViewRowPostPaintEventArgs e)
{
using (SolidBrush b = new SolidBrush(this.dataGridView1.RowHeadersDefaultCellStyle.ForeColor))
{
e.Graphics.DrawString(e.RowIndex.ToString(System.Globalization.CultureInfo.CurrentUICulture), this.dataGridView1.DefaultCellStyle.Font, b, e.RowBounds.Location.X + 20, e.RowBounds.Location.Y + 4);
}
int rowHeaderWidth = TextRenderer.MeasureText(e.RowIndex.ToString(), dataGridView1.Font).Width;
if (rowHeaderWidth + 22 > dataGridView1.RowHeadersWidth)
{
dataGridView1.RowHeadersWidth = rowHeaderWidth + 22;
}
}
private void dataGridView2_RowPostPaint(object sender, DataGridViewRowPostPaintEventArgs e)
{
using (SolidBrush b = new SolidBrush(this.dataGridView2.RowHeadersDefaultCellStyle.ForeColor))
{
e.Graphics.DrawString(e.RowIndex.ToString(System.Globalization.CultureInfo.CurrentUICulture), this.dataGridView2.DefaultCellStyle.Font, b, e.RowBounds.Location.X + 20, e.RowBounds.Location.Y + 4);
}
int rowHeaderWidth = TextRenderer.MeasureText(e.RowIndex.ToString(), dataGridView2.Font).Width;
if (rowHeaderWidth + 22 > dataGridView2.RowHeadersWidth)
{
dataGridView2.RowHeadersWidth = rowHeaderWidth + 22;
}
}
//***************************
//****** Other Methods ******
//***************************
private void LoadFillDSVData(char delimiter)
{
//load file through openFileDialog
//some more openFileDialog code removed for simplicity
if (DataSets[typeOfDataset].BWorker != null || DataSets[typeOfDataset].BWorker.IsBusy)
{
Thread.Sleep(1000);
DataSets[typeOfDataset].BWorker.CancelAsync();
DataSets[typeOfDataset].BWorker.Dispose();
}
//if file was loaded, instantiate the class
//and populate it
dataGridView1.Rows.Clear();
dataGridView2.Rows.Clear();
typeOfDataset = 0;
DataSets[typeOfDataset] = new DSVDataSet();
DataSets[typeOfDataset].DataGrid = this.dataGridView1;
DataSets[typeOfDataset].BWorker = new BackgroundWorker();
DataSets[typeOfDataset].InputFile = openFileDialog1.FileName;
DataSets[typeOfDataset].FileName = Path.GetFileName(DataSets[typeOfDataset].InputFile);
DataSets[typeOfDataset].InputPath = Path.GetDirectoryName(DataSets[typeOfDataset].InputFile);
DataSets[typeOfDataset].Delimiter = delimiter;
//read file to get number of objects and attributes
DataSets[typeOfDataset].LoadFile(DataSets[typeOfDataset].InputFile, DataSets[typeOfDataset].Delimiter);
//ask to autodetect metadata
DialogResult dr = MessageBox.Show("Auto detect attributes?", "TestApp", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
switch (dr)
{
case DialogResult.Yes:
toolStripStatusLabel1.Text = "Autodetecting attributes...";
toolStripProgressBar1.Value = 0;
toolStripProgressBar1.Maximum = 100;
toolStripProgressBar1.Style = ProgressBarStyle.Continuous;
DataSets[typeOfDataset].AutoDetectMetadata(DataSets[typeOfDataset].Attributes);
break;
case DialogResult.No:
break;
default:
break;
}
}
public void UpdateProgressBarMethod(int progress)
{
if (progress > 99)
{
toolStripProgressBar1.Value = progress;
toolStripStatusLabel1.Text = "Done.";
}
else
{
toolStripProgressBar1.Value = progress;
}
}
}
}
还有一个类别：
DSVDataSet.cs
namespace TestApp
{
public class DSVDataSet : DataSet
{
static Form1 myForm = Form1.MyForm;
//constructor(s)
public DSVDataSet()
{
InputType = DataSetType.DSV;
}
//autodetects metadata from the file if
//the user wishes to do so
public override void AutoDetectMetadata(List<Attribute> attributeList)
{
BWorker.WorkerReportsProgress = true;
BWorker.WorkerSupportsCancellation = true;
BWorker.DoWork += worker_DoWork;
BWorker.ProgressChanged += worker_ProgressChanged;
BWorker.RunWorkerCompleted += worker_RunWorkerCompleted;
//send this to another thread as it is computationally intensive
BWorker.RunWorkerAsync(attributeList);
}
private void worker_DoWork(object sender, DoWorkEventArgs e)
{
List<Attribute> attributeList = (List<Attribute>)e.Argument;
using (StreamReader sr = new StreamReader(InputFile))
{
for (int i = 0; i < NumberOfAttributes; i++)
{
Attribute a = new Attribute();
attributeList.Add(a);
}
for (int i = 0; i < NumberOfObjects; i++)
{
string[] DSVLine = sr.ReadLine().Split(Delimiter);
int hoistedCount = DSVLine.Count();
string str = string.Empty;
for (int j = 0; j < hoistedCount; j++)
{
bool newValue = true;
str = DSVLine[j];
for (int k = 0; k < attributeList[j].Categories.Count; k++)
{
if (str == attributeList[j].Categories[k])
{
newValue = false;
}
}
if (newValue == true)
{
attributeList[j].Categories.Add(str);
//removed some code for simplicity
}
}
int currentProgress = (int)((i * 100) / NumberOfObjects);
if (BWorker.CancellationPending)
{
Thread.Sleep(1000);
e.Cancel = true;
return;
}
BWorker.ReportProgress(currentProgress); //report progress
}
}
e.Result = 100; //final result (100%)
}
private void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
int update = e.ProgressPercentage;
myForm.BeginInvoke(myForm.myDelegate, update);
}
private void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
if (e.Error != null)
{
return;
}
if (e.Cancelled)
{
return;
}
else
{
int update = (int)e.Result;
myForm.Invoke(myForm.myDelegate, update);
for (int i = 0; i < Attributes.Count; i++)
{
DataGridViewRow item = new DataGridViewRow();
item.CreateCells(DataGrid);
item.Cells[0].Value = Attributes[i].Name;
switch (Attributes[i].Type)
{
case AttributeType.Categorical:
item.Cells[1].Value = "Categorical";
break;
//removed some cases for simplicity
default:
item.Cells[1].Value = "Categorical";
break;
}
item.Cells[2].Value = Attributes[i].Convert;
DataGrid.Rows.Add(item);
}
BWorker.Dispose();
}
}
}
}
长话短说，我在DSVDataset.cs中有一个backGroundWorker，它可以进行一些"繁重的计算"，这样UI就不会冻结（这是新的），我使用委托让后台线程与UI线程通信，以更新一些进度条值。如果用户决定创建一个新的DSVDataSet（通过cSVToolStripMenuItem_Click或tSVToolStrip MenuItem_Click），那么我在任何我认为合适的地方添加了一些If，以检查是否已经有backGroundWorker在运行：如果已经有，请调用CancelAsync，使其停止正在执行的任何操作，然后进行处置。现在，有时当我试图在backGroundWorker可能正在运行时退出Form1时（例如检查Form1_FormClosing），我会在这篇文章的标题中看到错误。该错误将我带到DSVDataSet.cs:中的这段代码
private void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
int update = e.ProgressPercentage;
myForm.BeginInvoke(myForm.myDelegate, update);
}
按F10进入Program1.cs:
Application.Run(new Form1());
基于我读到的另一篇stackoverflow帖子(http://stackoverflow.com/questions/513131/c-sharp-compile-error-invoke-or-begininvoke-cannot-be-called-on-a-control-unti，看看答案），我通过公开Main类本身的实例来实现该逻辑，因此它总是指向Main的这个实例。因此，在Form1.cs:中
private static Form1 myForm;
public static Form1 MyForm
{
get
{
return myForm;
}
}
public Form1()
{
InitializeComponent();
if (myForm == null)
{
myForm = this;
}
}
在DSVDataset.cs:中
static Form1 myForm = Form1.MyForm;
我在任何需要的地方都使用myForm。
尽管如此，我还是无法克服这个错误，所以我只能假设我没有正确地实现该解决方案，或者我在处理backGroundWorkers时出错了。任何帮助都将不胜感激，我尽我所能做到尽可能详细（希望这不是一个过度：）
问候
正如dBear所说，在表单被处理后，后台工作人员很可能仍在触发进度更改事件。最好是在后台工作人员完成之前阻止窗体关闭，或者在关闭窗体之前杀死后台工作人员。无论您选择哪种选项，最好使用事件进行这种通信。将以下事件定义添加到DSVDataSet，并修改进度更改的事件处理程序：
public event ProgressChangedEventHandler ProgressChanged;
private void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
if (ProgressChanged != null) {
ProgressChanged(this, e);
}
}
完成后，您将需要在Form1中进行更改，以便在创建DSVDataSet的新实例后，添加一个事件处理程序：
dsv.ProgressChanged += new ProgressChangedEventHandler(dsv_ProgressChanged);
将显示进度所需的任何代码放入dsv_ProgressChanged的主体中，类似于：
void dsv_ProgressChanged(object sender, ProgressChangedEventArgs e) {
myForm.Invoke(myForm.myDelegate, update);
}
代码太多，无法理解所有代码。但是当你关闭表单时，后台工作人员似乎仍在工作，因此，后台工作程序的进度更改会使你的程序崩溃。
对于快速解决方案，当进度发生变化时检查表单状态，因为我对winform没有太多经验，但它必须有一个方法来检查表单是否正在关闭或处理。
不建议这样做，因为它将耦合UI和逻辑。
首先，它看起来就像您正在尝试创建Form1的单例实例。最好的方法是创建一个带有静态方法、属性或变量的私有构造函数来创建表单的新实例：
public class Form1 : Form
{
private static Form1 instance;
public static Form1 Instance
{
get
{
if(instance == null) { instance = new Form1(); }
return instance;
}
}
private Form1()
{
......
}
}
然后更改：
Application.Run(new Form1());
收件人：
Application.Run(Form1.Instance);
然后，您可以在任何其他类中使用Form1.Instance来访问主窗口。现在，窗口句柄错误通常与没有在主线程上创建的窗体（Form1）相关联。
按照我提供的模式可能会解决您的问题。