2

我有带有自定义字体和计时器的标签，它们会改变标签中的值。我的应用程序开始最小化。当我显示应用程序时，有时会显示异常并且标签中的文本是红十字。

在这里我尝试调用异步方法来更改标签文本

private void timer1_Tick(object sender, EventArgs e)
    {
        // create a delegate of MethodInvoker poiting to showTime function.
        MethodInvoker simpleDelegate = new MethodInvoker(showTime);
        // Calling showTime Async
        simpleDelegate.BeginInvoke(null, null);
    }

字体加载

public Form1()
    {
        InitializeComponent();

        SystemEvents.SessionSwitch += new SessionSwitchEventHandler(SystemEvents_SessionSwitch); //event handler for windows lock

        File.WriteAllBytes(appPath + "\\font.ttf", Resources.font); //copy font from resources

        try
        {
            PrivateFontCollection pfc = new PrivateFontCollection();
            pfc.AddFontFile(appPath + @"/font.ttf");
            label1.Font = new Font(pfc.Families[0], 11, FontStyle.Bold);
        }
        catch
        {
            MessageBox.Show("Failed to load nice font." + "\r\n" + "Using standart font instead.", "Time app", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
        }

    }

这是标签tet更改的方法

private void showTime()
    {
        label1.Text = time.ToString();
    }

** * **异常文本** * ****

System.ArgumentException: Parameter is not valid.
at System.Drawing.FontFamily.GetName(Int32 language)
at System.Drawing.FontFamily.get_Name()
at System.Windows.Forms.Internal.WindowsFont.FromFont(Font font, WindowsFontQuality fontQuality)
at System.Windows.Forms.Internal.WindowsGraphicsCacheManager.GetWindowsFont(Font font, WindowsFontQuality fontQuality)
at System.Windows.Forms.TextRenderer.MeasureText(String text, Font font, Size proposedSize, TextFormatFlags flags)
at System.Windows.Forms.Layout.LayoutUtils.MeasureTextCache.GetUnconstrainedSize(String text, Font font, TextFormatFlags flags)
at System.Windows.Forms.Layout.LayoutUtils.MeasureTextCache.TextRequiresWordBreak(String text, Font font, Size size, TextFormatFlags flags)
at System.Windows.Forms.Label.CreateTextFormatFlags(Size constrainingSize)
at System.Windows.Forms.Label.CreateTextFormatFlags()
at System.Windows.Forms.Label.OnPaint(PaintEventArgs e)
at System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer)
at System.Windows.Forms.Control.WmPaint(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.Label.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

问题：当我使用自定义字体时如何摆脱这个异常？

4

2 回答 2

6

问题是变量中的PrivateFontCollection实例pfc超出范围，有时在第一次绘制控件之前被收集（这似乎在之后获得了对该实例的强引用）。

将实例移出方法以防止 GC 收集它：

class Form1 : Form
{
    readonly PrivateFontCollection _pfc = new PrivateFontCollection();
    public Form1()
    {
        ...

        _pfc.AddFontFile(appPath + @"/font.ttf");

        ...
    }
}
于 2017-05-26T20:37:11.037 回答
-1

这是在此处的另一个问题中使用的示例。它显示了你需要什么。https://web.archive.org/web/20141224204810/http://bobpowell.net/embedfonts.aspx

于 2012-08-06T13:52:16.607 回答