如何將變量從一類發送到另一類

Question

這是現在的代碼，在我之前遺漏了一些代碼的同時，我將包括該程序的所有代碼。 由於使用星號和///強調了您的幫助，我更改了一些位。第一類是在直接編輯表單時從Windows Forms創建的標准類。

namespace DistanceEstimatorFinal
{
    public partial class Form1 : Form
    {
        private bool saved;

        public Form1()
        {

            dataPoints mydataPoints = new dataPoints();
            InitializeComponent();
            dataPoint a = mydataPoints.getItem(0);
            latTextBox.Text = a.CurLatitude;
            longTextbox.Text = a.CurLongtitude;
            eleTextBox.Text = a.CurElevation;
            saved = true;

        }             

        private void latTextBox_TextChanged(object sender, EventArgs e)
        {

        }

        private void openDataListToolStripMenuItem_Click(object sender, EventArgs e)
        {
            OpenFileDialog ofd = new OpenFileDialog();
            ofd.Filter = "CSV files (*.csv)|*.csv|Text files ( *.txt)|*.txt |All files (*.*)|*.*";
            if (ofd.ShowDialog(this).Equals(DialogResult.OK))
            {
                *var dp = new dataPoints (ofd.FileName);* /////

            }
        }       



        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (saved)
            {
                if (MessageBox.Show("Save?", "Data Not Saved", MessageBoxButtons.YesNo).Equals(DialogResult.Yes))
                {
                    SaveFileDialog sfd = new SaveFileDialog();
                    sfd.ShowDialog();

                }

            }
        }

        private void saveAsToolStripMenuItem_Click(object sender, EventArgs e)
        {
            SaveFileDialog sfd1 = new SaveFileDialog();
            sfd1.Filter = "CSV files (*.csv)|*.csv|Text files ( *.txt)|*.txt |All files (*.*)|*.*";
            sfd1.ShowDialog();
        }

    }
}     

此類旨在讀取文件中的數據，我目前正在對其進行調整，以從open函數讀取文件。

namespace DistanceEstimatorFinal
{    
    public class dataPoints
    {              
        List<dataPoint> Points;
        string p;

        public dataPoints(string path)
        {
            p = path;
            Points = new List<dataPoint>();

            StreamReader tr = new StreamReader(p);

            string input;
            while ((input = tr.ReadLine()) != null)
            {
                string[] bits = input.Split(',');
                dataPoint a = new dataPoint(bits[0],bits[1],bits[2]);              
                Points.Add(a);  


            }

            tr.Close();
        }





        internal dataPoint getItem(int p)
        {
            if (p < Points.Count)
            {
                return Points[p];
            }
            else
                return null;
        }
    }

}

該文件包含三個變量距離，緯度和經度。

namespace DistanceEstimatorFinal
{
    class dataPoint
    {
        private string latitude;
        private string longtitude;
        private string elevation;

        public dataPoint()                               //Overloaded incase no value available
        {
            latitude = "No Latitude Specified";
            longtitude = "No Longtitude Specified";
            elevation = "No Elevation Specified";

        }

        public dataPoint(string Latitude, string Longtitude, string Elevation)
        {

            // TODO: Complete member initialization
            this.latitude = Latitude;
            this.longtitude = Longtitude;
            this.elevation = Elevation;

        }

        public string CurLongtitude { get { return this.longtitude; } }
        public string CurLatitude { get { return this.latitude; } }
        public string CurElevation { get { return this.elevation; } }

    }

Answer 1

你pathFile是一個方法局部變量，所以它的不同之處在於方法（這里的身體inacccesible任何地方openDataListToolStripMenuItem_Click ）。

您可以在dataPoints構造函數中添加一個參數，以將該值傳遞給類：

public class dataPoints
{
    List<dataPoint> Points;
    public dataPoints(string path)
    {
        Points = new List<dataPoint>();
        //here `path` from constructor arguments
        TextReader tr = new StreamReader(path); 
        //...rest part of your code
    }

除此之外，您還必須將值傳遞給此構造函數。 您沒有顯示代碼，必須創建dataPoints實例。

var dp = new dataPoints(pathFile);

但要記住， pathFile只能訪問在openDataListToolStripMenuItem_Click 。 因此，您應該在dataPoints創建dataPoints ，或者將pathFile設置為表單的字段，以便可以使用該表單的任何方法對其進行訪問。 然后，您將有機會以這種形式的任何方法訪問pathFile 。

---

根據您以前的帖子 ，它應該類似於：

private void openDataListToolStripMenuItem_Click(object sender, EventArgs e)
{
    OpenFileDialog ofd = new OpenFileDialog();
    ofd.Filter = "CSV files (*.csv)|*.csv|Text files ( *.txt)|*.txt |All files (*.*)|*.*";
    if (ofd.ShowDialog(this).Equals(DialogResult.OK))
    {            
        //actually you don't even need to have a separate `pathFile` variable
        //just pass the value from the dialog straight to your `dataPoints` object
        var dp = new dataPoints(ofd.FileName);
        //...rest of your code
    }
}

PS：脫離主題，但請考慮閱讀《 MSDN名稱指南》