WPF的BackgroundWorker进度栏遇到的困难 [英] BackgroundWorker WPF difficulties with Progress Bar
问题描述
我正在开发WPF，C#应用程序，我必须读取一个很大的CSV文件并写入数据库.这个过程需要很长时间，所以我至少要显示一个进度条，随着进度的临近，进度条的大小会逐渐增加.
I am developing a WPF, C# application and I have to read a very big CSV file and write to a database. This process takes a long time so I want to at least show a progress bar that grows in size as it nears completition.
现在，我在顶部有以下代码:
Now, I have the following code at the top:
private readonly BackgroundWorker worker = new BackgroundWorker();
然后在循环中，我有这个:
Then inside the loop I have this:
worker.WorkerReportsProgress = true;
worker.ReportProgress((100 * i) / 10000);
并且我有一个像这样的私人潜艇:
and I have a private sub like this:
private void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
prgBar.Value = Math.Min(e.ProgressPercentage, 100);
}
但是，我没有看到进度条更新或发生任何事情，程序仍然挂起.我在做错什么吗?
Yet I don't see the progress bar updating or anything happening, program still hangs. Am I doing something wrong?
更新:在此处尝试了MSDN指南 http ://msdn.microsoft.com/zh-cn/library/cc221403%28v=vs.95%29.aspx ，但我不知何故无法在该示例中使用它.我当然调整了循环部分.嘿.它仍然保持空闲状态，没有任何更新.哎呀，我要做的就是得到一个小的计数器，该计数器在每次读取和添加一行时都会增加.
UPDATE: Tried the MSDN guide here http://msdn.microsoft.com/en-us/library/cc221403%28v=vs.95%29.aspx and I somehow failed to get it working with that example. I adjusted the looping part of course. Heh. It still stays idle and nothing updates. Heck, all I want to do is get a small counter that increases every time a line is read and added.
更新的代码:
private BackgroundWorker bw = new BackgroundWorker();
public Process()
{
bw.WorkerReportsProgress = true;
bw.WorkerSupportsCancellation = true;
bw.DoWork += new DoWorkEventHandler(bw_DoWork);
bw.ProgressChanged += new ProgressChangedEventHandler(bw_ProgressChanged);
bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bw_RunWorkerCompleted);
}
private void bw_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker worker = sender as BackgroundWorker;
// Perform a time consuming operation and report progress.
int d = 0;
Microsoft.Win32.OpenFileDialog dlg = new Microsoft.Win32.OpenFileDialog();
// Set filter for file extension and default file extension
dlg.DefaultExt = ".csv";
dlg.Filter = "CSV File (*.csv)|*.csv";
dlg.Title = "file";
// Display OpenFileDialog by calling ShowDialog method
Nullable<bool> result = dlg.ShowDialog();
if (result == true)
{
// Open document
string filename = dlg.FileName;
List<String[]> fileContent = new List<string[]>();
using (FileStream reader = File.OpenRead(@filename)) // mind the encoding - UTF8
using (TextFieldParser parser = new TextFieldParser(reader))
{
using (SqlConnection conn = new SqlConnection(Classes.PublicVariables.Connection))
{
parser.Delimiters = new[] { "," };
parser.HasFieldsEnclosedInQuotes = true;
while (!parser.EndOfData)
{
string[] line = parser.ReadFields();
fileContent.Add(line);
SqlCommand comm = QUERYANDPARAMETERS
d += 1;
comm.ExecuteNonQuery();
worker.ReportProgress((d * 10));
}
}
}
}
private void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
lblCount.Content = "Complete";
}
private void bw_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
this.lblCount.Content = (e.ProgressPercentage.ToString() + "%");
}
当工人奔跑时，我感到非常高兴.
I am getting an excerption when the worker runs.
An exception of type 'System.NullReferenceException' occurred inSolution.exe but was not handled in user code
其他信息:对象引用未设置为对象的实例.
Additional information: Object reference not set to an instance of an object.
UPDATE3
让它正常工作！我需要的是与上面相同的代码，但这是
Got it working! All I needed was the same code as above but this:
if (bw.IsBusy != true)
{
bw.RunWorkerAsync();
}
else
{
bw_DoWork(null, null);
}
在事件处理程序中按下按钮.
In the event handler for the button press.
推荐答案
这不会按原样编译，但应该使您朝正确的方向开始
This will not compile as-is, but should get you started in the right direction:
private readonly BackgroundWorker worker
= new BackgroundWorker { WorkerReportsProgress = true };
public MainWindow()
{
InitializeComponent();
worker.DoWork += worker_DoWork;
worker.ProgressChanged += worker_ProgressChanged;
}
private void worker_DoWork(object sender, DoWorkEventArgs doWorkEventArgs)
{
// Do some long process, break it up into a loop so you can periodically
// call worker.ReportProgress()
worker.ReportProgress(i); // Pass back some meaningful value
}
private void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
prgBar.Value = Math.Min(e.ProgressPercentage, 100);
}
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