Question

我创建了一个包含n个实例的计时器应用程序。当我试图运行该应用程序时，它向我显示一条错误，指出“无法将类型为'System.Windows.Forms.Timer'的对象强制转换为'System.Windows.Forms.Button'”

private void button1_Click(object sender, EventArgs e)
        {
            timer = new Timer();

            timer.Interval = 1000;
            timer.Tick += new System.EventHandler(t_Tick);

            panel.Add(AddNewPanel());
             panelId++;
        }

我的t_tick事件代码：

private void t_Tick(object sender, EventArgs e)
        {
            Button c = (Button)sender;
            Class1 t = findButtonByTag(c.Tag.ToString());
            if ((minutes == 0) && (hours == 0) && (seconds == 0))
            {
                timer.Stop();
                MessageBox.Show("Times up"); 
                t.totalSeconds.Enabled = true;
                t.totalSeconds.Text = "";
                //label12.Text = "";
                started = true;
                t.pause.Enabled = false;
                t.start.Text = "Start";
                t.time_in_hour.Text = "00";
                t.time_in_minutes.Text = "00";
                t.time_in_seconds.Text = "00";

            }
            else
            {
                //calculating the seconds that are being passed
                if (seconds < 1)
                {
                    seconds = 59;
                    if (minutes == 0)
                    {
                        minutes = 59;
                        if (hours != 0)
                            hours -= 1;

                    }
                    else
                    {
                        minutes -= 1;
                    }
                }
                else
                    seconds--;


                if (hours < 10)
                    t.time_in_hour.Text = "0" + hours.ToString();
                else
                    t.time_in_hour.Text = hours.ToString();
                if (minutes < 10)
                    t.time_in_minutes.Text = "0" + minutes.ToString();
                else
                    t.time_in_minutes.Text = minutes.ToString();
                if (seconds < 10)
                    t.time_in_seconds.Text = "0" + seconds.ToString();
                else
                    t.time_in_seconds.Text = seconds.ToString();

            }
        }

Answer 1

这是类代码公共类Class1 { 公共Class1（） { this.panel = new System.Windows.Forms.Panel（）; this.label1 = new Label（）; this.time = new Label（）; this.time_in_hour = new Label（）; this.time_in_minutes = new Label（）; this.time_in_seconds = new Label（）; this.colon1 = new Label（）; this.colon2 = new Label（）; this.start = new Button（）; this.totalSeconds = new TextBox（）; this.pause = new Button（）; this.delete = new Button（）; this.countTimers = new Label（）; } public Label countTimers {get;组; } public System.Windows.Forms.Panel panel {get;组; } public Label label1 {get;组; } 公共标签时间{get;组; } public label time_in_hour {get;组; } public label time_in_minutes {get;组; } public Label time_in_seconds {get;组; }

    public Label colon1 { get; set; }
    public Label colon2 { get; set; }

    public TextBox totalSeconds { get; set; }
    public Button start { get; set; }

    public Button pause { get; set; }

    public Button delete { get; set; }
}

}

Answer 2

Timer调用t_Tick事件而不是Button。使用Timer作为发件人而不是Button

进行修复

无法转换'System.Windows.Forms.Timer'类型的对象在c＃中键入'System.Windows.Forms.Button'

2 个答案: