How to send more arguments in C# backgroundworker progressed changed event

问题

I understand how we can pass one variable(progresspercentage) to "progresschanged" function , like so.

backgroundWorker1.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);

...

worker.ReportProgress(pc);

...

private void backgroundWorker1_ProgressChanged(object sender,
ProgressChangedEventArgs e)
{
   this.progressBar1.Value = e.ProgressPercentage;
}

But I want to pass more variables to this function, some thing like:

worker.ReportProgress(pc,username,score);

...

private void backgroundWorker1_ProgressChanged(object sender,
ProgressChangedEventArgs e)
{
   this.progressBar1.Value = e.ProgressPercentage;
   this.currentUser.Value = e.UserName;  //as string
   this.score.Value = e.UserScore;  //as int
}

sorry I'm new to c#, could someone give me an example.

回答1:

The ReportProgress method of background worker component is overloaded to pass percentage and an object typed state value:

public void ReportProgress(int percentProgress, Object userState)

In your usage requirement you can concatenate the UserName and Score with a char separator, and so pass the multiple values inside the userState parameter; and split them inside the ProgressChanged() event when it is raised. You can also create a small property based class- fill it with values and pass using the userState object typed parameter.

For a sample example of how to use the overloaded ReportProgress method, please look at the below MSDN link:

http://msdn.microsoft.com/en-us/library/a3zbdb1t.aspx

回答2:

In case anyone is looking for a comprehensive answer:

Fast & simple approach would be object[] as in:

worker.ReportProgress(i, new object[] { pc, username, score });

Fast & Type-safe approach would be System.Tuple<> as in:

worker.ReportProgress(i, new System.Tuple<object, string, float>(pc, username, score));

Best practice would be to write your custom class (or maybe inherit from System.Tuple<>).

public class PcUsernameScore
{
    public object PC;
    public string UserName;
    public float Score;
    public PcUsernameScore(object pc, string username, float score)
    {
        PC = pc; Username = username; Score = score;
    }
}

public class PcUsernameScore : System.Tuple<object, string, float>
{
    public PcUsernameScore(object p1, string p2, float p3) : base(p1, p2, p3) { }
}

to have something like:

worker.ReportProgress(i, new PcUsernameScore(pc, username, score));

- C# 7.1

Inferred Tuple feature:

worker.ReportProgress(i, (pc: "pc", username: "me", score: 0));

回答3:

Create a data transfer object with properties for the items you want to pass and and then pass it in as the user state. In the OO world, the answer is almost always to create another object.

来源：https://stackoverflow.com/questions/7332632/how-to-send-more-arguments-in-c-sharp-backgroundworker-progressed-changed-event

标签

events

backgroundworker