标签内容和进度条

Question

我创建 Windows 窗体应用程序并添加进度条以显示加载文件的进度，并在进度条上方添加标签以显示每个文件的路径，但总路径很长并且出现在行中，但我的宽度形式对于某些路径没有全部出现，我在堆栈溢出和谷歌中看到了不止一种解决方案，但没有用，因为使自动大小为 false ，停靠填充和更改大小。我想要动态更改路径长度的方法。

Answer 1

要显示整个路径（例如换行），您需要将 Label 的 Height 设置为某个值，例如 50。所以它可能类似于Label 与50 的Height 和300 的Width，然后在其下方是ProgressBar。

此外，您的问题似乎是您正在主线程上执行长时间运行的操作。这就是Label 不令人耳目一新的原因。您需要利用BackgroundWorker。所以，为它添加一个类变量：

private BackgroundWorker _worker = new BackgroundWorker();

然后在ctor 中执行此操作：

_worker.WorkerReportsProgress = true;
_worker.DoWork += DoBackgroundWork;
_worker.ProgressChanged += ReportProgress;

然后对于那些处理程序：

private void DoBackgroundWork(object sender, DoWorkEventArgs e)
{
    // do the work you're doing in here -but add the below line when you want
    // to update the text of your label
    _worker.ReportProgress(1, "Your label text here");
}

private void ReportProgress(object sender, ProgressChangedEventArgs e)
{
    this.label.Text = e.UserState as string;
}

---

您可能要考虑的最后一件事，就是将字符串切断到与标签长度接近 的距离，而不是尝试将其包裹起来。下面是一组方法，证明了一个可能的解决方案。

需要注意的一点是，截断过程利用了 bin 搜索，因此它不是难以置信准确。我的意思是什么？好吧，假设您有一个长度为 150 个字符的字符串（如下例中的字符串），并且第一次将其切成两半并测量字符串。如果该宽度小于最大宽度（例如Label 的宽度），它只会返回该字符串。这行得通，但标签的长度上可能有剩余空间，并且可能会截断更少的字符。

为了使这个更准确，你必须进行更多的传球，而 IMO，这对于进行可枚举的传球来说还不够重要。

public partial class Form1 : Form
{
    string[] chars = new string[]
    {
        "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z",
        "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"
    };

    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        var filePath = BuildString(150);
        var g = this.label1.CreateGraphics();
        var size = g.MeasureString(filePath, this.Font);
        var oneCharacterLen = (size.Width / (float)filePath.Length);
        if (size.Width > ((float)this.label1.Width - (oneCharacterLen * 3f)))
        {
            this.label1.Text = CutoffStringBinSearch(g, string.Format("{0}", filePath), 0, this.label1.Width);
        }
    }

    private string CutoffStringBinSearch(Graphics g, string s, int startIndex, int maxWidth)
    {
        var midPoint = (s.Length - startIndex) / 2;
        var subString = string.Format("{0}...", s.Substring(startIndex, midPoint));

        var len = g.MeasureString(subString, this.Font);
        if (len.Width > (float)maxWidth) { return CutoffStringBinSearch(g, s.Substring(startIndex, midPoint), 0, maxWidth); }

        return subString;
    }

    private string BuildString(int len)
    {
        string[] s = new string[len];
        var random = new Random(0);
        for (int i = 0; i < len; i++)
        {
            s[i] = chars[random.Next(0, chars.Length - 1)];
        }
        return string.Join("", s);
    }
}

Answer 2

using System;

使用 System.ComponentModel; 使用 System.Windows.Forms；

命名空间BackgroundWorkerSimple { 公共部分类Form1：表格 { 公共表格1（） { 初始化组件（）； backgroundWorker1.WorkerReportsProgress = true; backgroundWorker1.WorkerSupportsCancellation = true; }

    private void startAsyncButton_Click(object sender, EventArgs e)
    {
        if (backgroundWorker1.IsBusy != true)
        {
            // Start the asynchronous operation.
            backgroundWorker1.RunWorkerAsync();
        }
    }

    private void cancelAsyncButton_Click(object sender, EventArgs e)
    {
        if (backgroundWorker1.WorkerSupportsCancellation == true)
        {
            // Cancel the asynchronous operation.
            backgroundWorker1.CancelAsync();
        }
    }

    // This event handler is where the time-consuming work is done. 
    private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    {
        BackgroundWorker worker = sender as BackgroundWorker;

        for (int i = 1; i <= 10; i++)
        {
            if (worker.CancellationPending == true)
            {
                e.Cancel = true;
                break;
            }
            else
            {
                // Perform a time consuming operation and report progress.
                System.Threading.Thread.Sleep(500);
                worker.ReportProgress(i * 10);
            }
        }
    }

    // This event handler updates the progress. 
    private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
        resultLabel.Text = (e.ProgressPercentage.ToString() + "%");
    }

    // This event handler deals with the results of the background operation. 
    private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        if (e.Cancelled == true)
        {
            resultLabel.Text = "Canceled!";
        }
        else if (e.Error != null)
        {
            resultLabel.Text = "Error: " + e.Error.Message;
        }
        else
        {
            resultLabel.Text = "Done!";
        }
    }
}

}

Answer 3

使用 labelX.Refresh()。

label1.Text = "First text";
Thread.Sleep(1500); //*This line is only for testing purpose as the change is pretty quick*. 
progressBar1.Value = 50;
label1.Refresh();
label1.Text = "Second text";
Thread.Sleep(1500); //*This line is only for testing purpose as the change is pretty quick*. 
label1.Refresh();