Question

我想将一个额外的参数传递给我的DoWork方法，但我得到的编译错误为No overload for 'backgroundWorker1_DoWork' matches delegate 'System.ComponentModel.DoWorkEventHandler'

这是我的语法，我该怎么做才能解决这个问题？

namespace Testing
{
public partial class Form1 : Form1
{
    public static string[] employeeName;

    public Form1()
    {
        InitializeComponent();
        backgroundWorker1.WorkerReportsProgress = true;
        backgroundWorker1WorkerSupportsCancellation = true;
        backgroundWorker1.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork);
        backgroundWorker1.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);
    }
    private void btn1_Click(object sender, EventArgs e)
    {
        backgroundWorker1.RunWorkerAsync(employeeName);
    }
    private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e, string[] employeeName)
    {
        //Just for example sake
        for (int q = employeeName.GetLowerBound(0); q <= employeeName.GetUpperBound(0); q++)
        {
          MessageBox.Show(employeeName[q];
        }
    }
}
}

Answer 1

DoWorkEventHandler具有以下定义：

public delegate void DoWorkEventHandler(
    Object sender,
    DoWorkEventArgs e
)

您无法添加第三个参数。您想要获取的对象位于DoWorkEventArgs.Argument属性中。

public partial class Form1 : Form1
{
    public static string[] employeeName;

    public Form1()
    {
        InitializeComponent();
        backgroundWorker1.WorkerReportsProgress = true;
        backgroundWorker1WorkerSupportsCancellation = true;
        backgroundWorker1.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork);
        backgroundWorker1.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);
    }
    private void btn1_Click(object sender, EventArgs e)
    {
        backgroundWorker1.RunWorkerAsync(employeeName);
    }
    private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    {
        string[] employeeName = (string[])e.Argument;
        //Just for example sake
        for (int q = employeeName.GetLowerBound(0); q <= employeeName.GetUpperBound(0); q++)
        {
          MessageBox.Show(employeeName[q];
        }
    }
}

使用BackgroundWorker编译错误

1 个答案: