在為我的項目實現導出 util 的過程中，我遇到了上傳文件期間阻止 UI 的問題?；旧蠁栴}是在異步任務期間我無法更新進度欄。我已經嘗試了幾種解決方案。一般來說，當我調用exportPopUp.ShowDialog()時，它會阻止copyAttachment()的執行，并且整個邏輯在關閉表單后完成。我決定使用 Show() 但當我這樣做時，表單不存在（全灰色）這是我的背景邏輯： private void exportButton_Click(object sender, EventArgs e) { // get files int row = reportsDataGrid.CurrentCell.RowIndex; if (row >= 0) { string problemId = reportsDataGrid.Rows[row].Cells[0].Value.ToString(); AC.Trace.I("Problem Id", problemId); FolderBrowserDialog dlgFolderBrowser = new FolderBrowserDialog(); dlgFolderBrowser.Description = "Select folder to save Report files!"; DialogResult result = dlgFolderBrowser.ShowDialog(); if (result == DialogResult.OK) { string folderName = dlgFolderBrowser.SelectedPath; AC.Trace.I("Destination folder name", folderName); CIS.PRS.Data.Attachments attachments = jampPrsService.ReportFiles(problemId); processAttachments(attachments, folderName, problemId); } } } private async void processAttachments(Attachments attachments, string folderName, string problemId) { this.exportPath = folderName + "\\" + problemId; cts = new CancellationTokenSource(); this.exportPopUp = new exportPopUp(attachments.Size(), cts); this.exportPopUp.ExportFinished += ExportPopUp_ExportFinished; exportPopUp.setExportLabelText("Exporting problem report " + problemId); exportPopUp.ShowDialog(); await copyAttachments(attachments, folderName, problemId); }一般來說，整個邏輯按我的預期工作，但我無法同時復制任務和更新進度欄。提前致謝
1 回答
翻閱古今
TA貢獻1780條經驗 獲得超5個贊
問題在于從異步處理切換到同步處理。您甚至可以在代碼中執行兩次。
如果您從 async wait 開始，則需要在整個調用層次結構中繪制它。
1) 從點擊處理程序開始。async void這應該是層次結構中的唯一方法。在這里等下一篇
private async void exportButton_Click(object sender, EventArgs e)
{
await processAttachments(attachments, folderName, problemId);
}
2）使下一個調用的方法返回一個任務并使用，Show以便copyAttachments隨后執行并可以等待
return Task here
|
v
private async Task processAttachments(Attachments attachments, string folderName, string problemId)
{
this.exportPath = folderName + "\\" + problemId;
cts = new CancellationTokenSource();
this.exportPopUp = new exportPopUp(attachments.Size(), cts);
this.exportPopUp.ExportFinished += ExportPopUp_ExportFinished;
exportPopUp.setExportLabelText("Exporting problem report " + problemId);
exportPopUp.Show(); // <= !
await copyAttachments(attachments, folderName, problemId);
}
3) 使用返回的任務fs.WriteAsync并等待它。讓該copy方法再次返回一個 Task 以將其向上傳播：
private void copy(Attachment attachment, string folderName, string problemId)
{
...
try
{
using (fs = new FileStream(Path.Combine(exportPath, attachment.Name), FileMode.Create))
{
awaitfs.WriteAsync(attachment.Data, 0, attachment.Data.Length, this.cts.Token);
fs.Flush();
fs.Close();
this.exportPopUp.performProgressBarStep();
}
}
...
4）等待復制方法（如果你想逐個復制附件）：
private async Task copyAttachments(Attachments attachments, string folderName, string problemId)
{
foreach (Attachment attachment in attachments.attachments)
{
await copy(attachment, folderName, problemId));
}
}
這應該會產生一個可行的解決方案，其中兩個表單都將保持響應，并且您將看到進度條已填滿。
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