如何在列表框中查找项目？

Question

I am creating an application where I have a ListBox which has items that are read in from a text file using StreamReader . I have created a search form but I'm not sure what to do next. Can anyone give me some suggestions please? Here is my code:

My code for the ListBox (sorry it's so long)

public partial class frmSwitches : Form
{
    public static ArrayList switches = new ArrayList();
    public static frmSwitches frmkeepSwitches = null;
    public static string inputDataFile = "LeckySafe.txt";
    const int numSwitchItems = 6;
    public frmSwitches()
    {
        InitializeComponent();
        frmkeepSwitches = this;
    }

    private void btnDevices_Click(object sender, EventArgs e)
    {
        frmDevices tempDevices = new frmDevices();
        tempDevices.Show();
        frmkeepSwitches.Hide();
    }

    private bool fileOpenForReadOK(string readFile, ref StreamReader dataIn)
    {
        try
        {
            dataIn = new StreamReader(readFile);
            return true;
        }
        catch (FileNotFoundException notFound)
        {
            MessageBox.Show("ERROR Opening file (when reading data in) - File could not be found.\n"
                + notFound.Message);
            return false;
        }
        catch (Exception e)
        {
            MessageBox.Show("ERROR Opening File (when reading data in) - Operation failed.\n"
                + e.Message);
            return false;
        }

    }

    private bool getNextSwitch(StreamReader inNext, string[] nextSwitchData)
    {
        string nextLine;
        int numDataItems = nextSwitchData.Count();

        for (int i = 0; i < numDataItems; i++)
        {
            try
            {
                nextLine = inNext.ReadLine();
                if (nextLine != null)
                    nextSwitchData[i] = nextLine;
                else
                {
                    return false;
                }
            }
            catch (Exception e)
            {
                MessageBox.Show("ERROR Reading from file.\n" + e.Message);
                return false;
            }
        }
        return true;
    }

    private void readSwitches()
    {
        StreamReader inSwitches = null;
        Switch tempSwitch;
        bool anyMoreSwitches = false;
        string[] switchData = new string[numSwitchItems];

        if (fileOpenForReadOK(inputDataFile, ref inSwitches))
        {
            anyMoreSwitches = getNextSwitch(inSwitches, switchData);

            while (anyMoreSwitches == true)
            {
                tempSwitch = new Switch(switchData[0], switchData[1], switchData[2], switchData[3], switchData[4], switchData[5]);

                switches.Add(tempSwitch);

                anyMoreSwitches = getNextSwitch(inSwitches, switchData);
            }
        }

        if (inSwitches != null) inSwitches.Close();
    }

    public static bool fileOpenForWriteOK(string writeFile, ref StreamWriter dataOut)
    {
        try
        {
            dataOut = new StreamWriter(writeFile);
            return true;
        }
        catch (FileNotFoundException notFound)
        {
            MessageBox.Show("ERROR Opening file (when writing data out)" +
                "- File could not be found.\n" + notFound.Message);
            return false;
        }
        catch (Exception e)
        {
            MessageBox.Show("ERROR Opening File (when writing data out)" +
                "- Operation failed.\n" + e.Message);
            return false;
        }

    }

    public static void writeSwitches()
    {
        StreamWriter outputSwitches = null;

        if (fileOpenForWriteOK(inputDataFile, ref outputSwitches))
        {
            foreach (Switch currSwitch in switches)
            {
                outputSwitches.WriteLine(currSwitch.getSerialNo());
                outputSwitches.WriteLine(currSwitch.getType());
                outputSwitches.WriteLine(currSwitch.getInsDate());
                outputSwitches.WriteLine(currSwitch.getElecTest());
                outputSwitches.WriteLine(currSwitch.getPatId());
                outputSwitches.WriteLine(currSwitch.getNumDevice());

            }
            outputSwitches.Close();
        }

        if (outputSwitches != null) outputSwitches.Close();
    }

    private void showListOfSwitches()
    {
        lstSwitch.Items.Clear();

        foreach (Switch b in switches)
            lstSwitch.Items.Add(b.getSerialNo()
                + b.getType() + b.getInsDate()
                + b.getElecTest() + b.getPatId() + b.getNumDevice());
    }

My code for the search form:

private void btnSearch_Click(object sender, EventArgs e)
    {
        frmSearchSwitch tempSearchSwitch = new frmSearchSwitch();
        tempSearchSwitch.Show();
        frmkeepSwitches.Hide();
    } 

Answer 1

If using a List<T> and lambda is not possible for you then go no farther.

Here I use a List<T> for the data source of a ListBox and mocked up data as where the data comes from is not important but here I am focusing on searching on a property within a class where a select is used to index the items then the where searches in this case) for a specific item, if found the index is used to move to the item. No code present for if not located as this is easy for you to do if the code here is something that is doable for you.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;

namespace ListBoxSearch_cs
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Button1_Click(object sender, EventArgs e)
        {
            var results =
                ((List<Item>)ListBox1.DataSource)
                    .Select((data, index) => new 
                    { Text = data.SerialNumber, Index = index })
                    .Where((data) => data.Text == "BB1").FirstOrDefault();
            if (results != null)
            {
                ListBox1.SelectedIndex = results.Index;
            }
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            var items = new List<Item>() {
            new Item {Identifier = 1, SerialNumber = "AA1", Type = "A1"},
            new Item {Identifier = 2, SerialNumber = "BB1", Type = "A1"},
            new Item {Identifier = 3, SerialNumber = "CD12", Type = "XD1"}
        };
            ListBox1.DisplayMember = "DisplayText";
            ListBox1.DataSource = items;
        }
    }
    /// <summary>
    /// Should be in it's own class file
    /// but done here to keep code together
    /// </summary>
    public class Item
    {
        public string SerialNumber { get; set; }

        public string Type { get; set; }

        public int Identifier { get; set; }

        public string DisplayText
        {
            get
            {
                return SerialNumber + " " + this.Type;
            }
        }
    }
}