Question

我在c＃中的windowsform有一个图表。当我第一次输入数据时，图表工作正常，当我点击清除时，一切都清除了。问题是当我第二次输入数据并且加载图形时，然后给出错误。

    private void button2_Click(object sender, EventArgs e)
    {
        //Graph codes
        if (p == 1)
        {
            if (t == 1)
            {
                if (txtFirstActual.Text == "" || txtSecondActual.Text == "" || txtThirdActual.Text == "" || txtFourthActual.Text == "")
                {
                    MessageBox.Show("Enter All Value Of Actual Years");
                }
                else
                {
                    int m = Convert.ToInt32(txtForecastingYear.Text);

                    int FirstYearValue = m - 4;
                    txtFirstYear.Text = FirstYearValue.ToString();

                    int SecondYearValue = m - 3;
                    txtSecondYear.Text = SecondYearValue.ToString();

                    int ThirdYearValue = m - 2;
                    txtThirdYear.Text = ThirdYearValue.ToString();

                    int FourthYearValue = m - 1;
                    txtFourthYear.Text = FourthYearValue.ToString();

                    double FirstActual = Convert.ToDouble(txtFirstActual.Text);
                    double SecondActual = Convert.ToDouble(txtSecondActual.Text);
                    double ThirdActual = Convert.ToDouble(txtThirdActual.Text);
                    double FourthActual = Convert.ToDouble(txtFourthActual.Text);


                    if (FirstActual == 0 && SecondActual != 0 && ThirdActual != 0 && FourthActual != 0) //if the user entered 3 years instead of 4
                    {

                        double sum = (SecondActual + ThirdActual + FourthActual) / 3;

                        listBox1.Items.Clear();
                        listBox1.Items.Add(sum);


                        this.chart1.Series["Sales"].Points.AddXY("Year-3", SecondActual);
                        this.chart1.Series["Sales"].Points.AddXY("Year-2", ThirdActual);
                        this.chart1.Series["Sales"].Points.AddXY("Year-1", FourthActual);
                        this.chart1.Series["Sales"].Points.AddXY("Year", sum);
                    }
                    else if (FirstActual != 0 && SecondActual == 0 && ThirdActual != 0 && FourthActual != 0)//if the user entered 3 years instead of 4
                    {
                        double sum = (FirstActual + ThirdActual + FourthActual) / 3;

                        listBox1.Items.Clear();
                        listBox1.Items.Add(sum);

                        this.chart1.Series["Sales"].Points.AddXY("Year-4", FirstActual);

                        this.chart1.Series["Sales"].Points.AddXY("Year-2", ThirdActual);
                        this.chart1.Series["Sales"].Points.AddXY("Year-1", FourthActual);
                        this.chart1.Series["Sales"].Points.AddXY("Year", sum);
                    }
                    else if (FirstActual != 0 && SecondActual != 0 && ThirdActual == 0 && FourthActual != 0)//if the user entered 3 years instead of 4
                    {
                        double sum = (FirstActual + SecondActual + FourthActual) / 3;

                        listBox1.Items.Clear();
                        listBox1.Items.Add(sum);

                        this.chart1.Series["Sales"].Points.AddXY("Year-4", FirstActual);
                        this.chart1.Series["Sales"].Points.AddXY("Year-3", SecondActual);

                        this.chart1.Series["Sales"].Points.AddXY("Year-1", FourthActual);
                        this.chart1.Series["Sales"].Points.AddXY("Year", sum);
                    }

                    else if (FirstActual != 0 && SecondActual != 0 && ThirdActual != 0 && FourthActual == 0)//if the user entered 3 years instead of 4
                    {

                        double sum = (FirstActual + SecondActual + ThirdActual) / 3;

                        listBox1.Items.Clear();
                        listBox1.Items.Add(sum);

                        this.chart1.Series["Sales"].Points.AddXY("Year-4", FirstActual);
                        this.chart1.Series["Sales"].Points.AddXY("Year-3", SecondActual);
                        this.chart1.Series["Sales"].Points.AddXY("Year-2", ThirdActual);

                        this.chart1.Series["Sales"].Points.AddXY("Year", sum);
                    }

                    else if (FirstActual != 0 && SecondActual != 0 && ThirdActual != 0 && FourthActual != 0)//if the user entered 4 years 
                    {

                        double sum = (FirstActual + SecondActual + ThirdActual + FourthActual) / 4;

                        listBox1.Items.Clear();
                        listBox1.Items.Add(sum);

                        this.chart1.Series["Sales"].Points.AddXY("Year-4", FirstActual);
                        this.chart1.Series["Sales"].Points.AddXY("Year-3", SecondActual);
                        this.chart1.Series["Sales"].Points.AddXY("Year-2", ThirdActual);
                        this.chart1.Series["Sales"].Points.AddXY("Year-1", FourthActual);
                        this.chart1.Series["Sales"].Points.AddXY("Year", sum);
                    }

                    else if (FirstActual != 0 && SecondActual != 0 && ThirdActual != 0 && FourthActual != 0)//if the user entered 4 years 
                    {

                        double sum = (FirstActual + SecondActual + ThirdActual + FourthActual) / 4;

                        listBox1.Items.Clear();
                        listBox1.Items.Add(sum);

                        MessageBox.Show(" Can't drow graph because there are no sales");
                    }
                }
                if (t == 0)
                {
                    MessageBox.Show("Enter Actual for Years");
                }
            }
            if (p == 0)
            {
                MessageBox.Show("Enter Wanted Year");
            }

那是我清晰的按钮： private void button1_Click（object sender，EventArgs e） { //清除按钮

        listBox1.Items.Clear();

        txtForecastingYear.Clear();
        txtFirstYear.Clear();
        txtSecondYear.Clear();
        txtThirdYear.Clear();
        txtFourthYear.Clear();

        chart1.Series.Clear();

        txtFirstActual.Clear();
        txtSecondActual.Clear();
        txtThirdActual.Clear();
        txtFourthActual.Clear();

        if (!String.IsNullOrEmpty(txtFirstActual.Text)) //if there is entry then make clear button available, if not the button will do nothing
        {
            // clear data
        }

Answer 1

看起来您的问题是，当您调用chart1.Series.Clear()时，它会清除chart1的所有索引，然后当您再次单击以填充图表时，您再也不会创建“销售”索引。您需要再次将“销售”图表添加到Series，然后才能调用其中的方法。

Answer 2

您的代码取决于“销售”系列，如下例所示：

this.chart1.Series["Sales"].Points.AddXY("Year-4", FirstActual);
this.chart1.Series["Sales"].Points.AddXY("Year-3", SecondActual);
this.chart1.Series["Sales"].Points.AddXY("Year-2", ThirdActual);
this.chart1.Series["Sales"].Points.AddXY("Year-1", FourthActual);
this.chart1.Series["Sales"].Points.AddXY("Year", sum);

但是，当您清除图表时，可能，您也清除图表系列，因此，第二次，图表无法识别系列“销售”

要纠正此问题，您需要检查该系列是否存在，如果该系列为空，则创建该系列。像这样：

if (this.chart1.Series.Count == 0)
{
    // Here you need to properly create the series
    this.chart1.Series.Add(new Series("Sales"));
}

这是一个通用示例，可能无法编译，因为我不知道您使用的系列类型或图表控件。所以一定要相应改变。

如果您不知道如何调用本系列的构造函数，请在Designer.cs文件中获取一个loog并复制此代码中的构造函数和属性，这样就可以了。

重新输入图表的数据

2 个答案: