I am stuck with the project C# and I don't know how to solve it. I have a text file "cars.txt" and it has this information:
1950
Nissan Sentra
Ford Focus
1951
Mazda5
Mazda3
Toyota
1952
Chevy
I have to have 2 list boxes and one button. The first list box supposed to search through the file and populate years and when user select year and click on the button and it displays the corresponding cars models for this specific year. I have thoughts about using StreamReader but I don't know how to start.
Your help appreciated
Create a dictionary of string lists that will contain car lists with the year a key as well as a list for the years:
private readonly Dictionary<int, List<string>> _carsByYear =
new Dictionary<int, List<string>>();
private readonly List<int> _years = new List<int>();
Then you can fill it with
List<string> cars = null;
foreach (string line in File.ReadLines(#"C:\Users\Me\cars.txt")) {
if (!String.IsNullOrWhiteSpace(line)) {
if (Int32.TryParse(line, out int year)) { // We have a year
if (_carsByYear.TryGetValue(year, out var existingList)) {
cars = existingList;
} else {
// Add a new list with year as the key
_years.Add(year);
cars = new List<string>();
_carsByYear.Add(year, cars);
}
} else { // We have a car
cars.Add(line);
}
}
}
Now you can assign _years to the DataSource of the first ListBox. You can get the selected year (SelectedIndexChanged event) with
int year = (int)listBox1.SelectedItem;
With this year, you can get the cars list with
var selectedCarList = _carsByYear[year];
Assign it to the DataSource of the second ListBox.
now the is no error but nothing displayed. This is a very challenging
assignment. everyone in my class is stuck.
Works fine for me. Here's a variation with some examples of how you could use it:
private readonly SortedList<int, SortedSet<string>> _carsByYear = new SortedList<int, SortedSet<string>>();
private void button1_Click(object sender, EventArgs e)
{
SortedSet<string> cars = null;
string fileName = System.IO.Path.Combine(
System.Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments),
"cars.txt");
foreach (string line in File.ReadLines(fileName))
{
if (!String.IsNullOrWhiteSpace(line))
{
if (Int32.TryParse(line, out int year))
{ // We have a year
if (!_carsByYear.ContainsKey(year))
{
cars = new SortedSet<string>();
_carsByYear.Add(year, cars);
}
else
{
cars = _carsByYear[year];
}
}
else
{ // We have a car
if (!cars.Contains(line))
{
cars.Add(line);
}
}
}
}
listBox1.DataSource = _carsByYear.Keys.ToList();
}
private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{
if (listBox1.SelectedIndex != -1)
{
listBox2.DataSource = _carsByYear[(int)listBox1.SelectedItem].ToList();
}
}
private void button2_Click(object sender, EventArgs e)
{
if (listBox1.SelectedIndex != -1 && listBox2.SelectedIndex != -1)
{
int year = (int)listBox1.SelectedItem;
string car = listBox2.SelectedItem.ToString();
label1.Text = year.ToString();
label2.Text = car;
}
else
{
label1.Text = "";
label2.Text = "";
}
}
If you still can't get it to work, give MORE DETAILS about the contents of the file and how you're supposed to use it in your interface.
Related
I wrote a program with C #
I have a combo box whose items are Binding from the database.I use AutoCompleteMode and AutoCompleteSource to search the combo box.But only when filtering does it find words whose first letter is the same as the input letter.While I need All items that contain these letters displayed.Is there a solution to this problem?
maybe this helps
// Example data
string[] data = new string[] {
"Absecon","Abstracta","Abundantia","Academia","Acadiau","Acamas",
"Ackerman","Ackley","Ackworth","Acomita","Aconcagua","Acton","Acushnet",
"Acworth","Ada","Ada","Adair","Adairs","Adair","Adak","Adalberta","Adamkrafft",
"Adams"
};
public Form1()
{
InitializeComponent();
}
private void comboBox1_TextChanged(object sender, EventArgs e)
{
HandleTextChanged();
}
// Handle Text Box that you Fill
private void HandleTextChanged()
{
var txt = comboBox1.Text;
var list = from d in data
where d.Tolower().Contains(comboBox1.Text.ToLower())
select d;
if (list.Count() > 0)
{
comboBox1.DataSource = list.ToList();
//comboBox1.SelectedIndex = 0;
var sText = comboBox1.Items[0].ToString();
comboBox1.SelectionStart = txt.Length;
comboBox1.SelectionLength = sText.Length - txt.Length;
comboBox1.DroppedDown = true;
return;
}
else
{
comboBox1.DroppedDown = false;
comboBox1.SelectionStart = txt.Length;
}
}
I have 2 Listbox and I want to check the first Listbox text so that I can add them to the second Listbox. Like, let's say that I have a car registration plate on the first Listbox ( 02-TH-93 ) and now I want to add on my second Listbox that same plate ( 02-TH-93 ) BUT if that plate doesn't exist on the first ListBox then it should just show a message error.
For example:
ListBox1:
02-TH-93
|
06-JK-58
|
07-HJ-95
|
02-FG-56
ListBox2:
02-TH-93
|
06-JK-58
|
07-HJ-95
|
45-ER-01 (Show message error now because there's no match of this registration plate on listbox1)
I tried this but it doesn't really make a lot of sense I guess:
parking.Entrance = textBoxEntrance.Text;
parking.Exit = textBoxExit.Text;
if(parking.Entrance == parking.Exit)
{
listBoxExit.Items.Add("Plate: " + parking.Exit + " Exited ");
}
Thanks
So if I have now understood correctly, this should work after your wishes. If you do not understand something, just ask again!
using System;
using System.Collections.Generic;
using System.Windows.Forms;
namespace plateManager
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button_LB1_Click(object sender, EventArgs e)
{
if (!string.IsNullOrWhiteSpace(txtbox1.Text))
lb1.Items.Add(txtbox1.Text);
else
MessageBox.Show("Please enter something!");
txtbox1.Text = "";
}
private void button_LB2_Click(object sender, EventArgs e)
{
//Asks if the textbox is empty or has space
if (!string.IsNullOrWhiteSpace(txtbox2.Text))
{
List<string> allPlates = new List<string>();
/*The list box will be read from top to bottom
and will add each entry in this list box to the list called "allPlates".*/
for (int i = 0; i < lb1.Items.Count; i++)
allPlates.Add(lb1.Items[i].ToString());
if (ExistsCheck(txtbox2.Text, allPlates))
lb2.Items.Add(txtbox2.Text);
else
MessageBox.Show("This license plate was not found!");
}
else
MessageBox.Show("Please enter something!");
//Reset the textbox
txtbox2.Text = "";
}
private bool ExistsCheck(string newPlate, List<string> allPlates)
{
//Each entry will be checked if it matches, if it does, the boolean is set to true and will be returned afterwards.
bool result = false;
foreach (var plate in allPlates)
if (plate.Equals(newPlate))
result = true;
return result;
}
}
}
I assume that your Listbox.ItemsSource is a list of strings so you could just loop through one of those lists and look for a match like this:
private bool IsInFirst(string plateToAdd, List<string> plates)
{
foreach(string plate in plates)
{
if (plate.Equals(plateToAdd))
{
return true;
}
}
return false;
}
If it returns true the list contains the plate to add and if it returns false it doesn't. This tutorial helped me.
I have created a variate as I understand it, so it asks if the "plate" is present in lb1. If yes then add it if not ignore it and make a message box
private bool ExistsCheck(string newPlate, List<string> allPlates)
{
bool result = false;
foreach (var plate in allPlates)
if (plate.Equals(newPlate))
result = true;
return result;
}
private void AddAndCheck_Click(object sender, EventArgs e)
{
List<string> allPlates = new List<string>();
for (int i = 0; i < lb1.Items.Count; i++)
allPlates.Add(lb1.Items[i].ToString());
if (ExistsCheck(tb_plate.Text, allPlates))
{
// If its return False
lb2.Items.Add(tb_plate.Text);
}
else
{
// If its return True
MessageBox.Show("It is not present in listbox 1");
}
}
Winforms, C#, VS2017
ImageList does not have an Insert method (however ListViewItemCollection does). I have tried a few different ways to insert a new image into the middle of a ListView and it's LargeImageList, but not getting it to work quite properly.
Anyone have any tried and true code that works properly?
This is what I have, but the images don't get synced properly to the items in the list.
protected void InsertThumbnail(string key, string keySelected)
{
var newImageList = new ImageList()
{
ImageSize = new Size(thumbWidth, thumbHeight)
};
var itemNew = new ListViewItem();
var foundSelected = false;
//lvAllPages.BeginUpdate();
for (int i = 0; i < lvAllPages.Items.Count; i++)
{
var item = lvAllPages.Items[i];
newImageList.Images.Add(item.Tag.ToString(), lvAllPages.LargeImageList.Images[i]);
if (item.Tag.ToString() == keySelected)
{
var image = batch.GetThumbnail(key);
newImageList.Images.Add(key, image);
itemNew = new ListViewItem()
{
BackColor = Color.Aquamarine,
ImageIndex = i,
Tag = key,
};
if (isLocal)
itemNew.Text = $"{GetFileName(key)} (insert) - {itemNew.ImageIndex}";
foundSelected = true;
}
if (foundSelected)
{
item.ImageIndex = item.ImageIndex + 1;
if (isLocal)
item.Text = $"{GetFileName(item.Tag.ToString())} - {item.ImageIndex}";
}
}
lvAllPages.LargeImageList.Dispose();
lvAllPages.LargeImageList = newImageList;
lvAllPages.Items.Insert(itemNew.ImageIndex, itemNew);
}
One more related thing, but not pertinent to the problems I am having. For anyone looking at this question and having similar issues, this helped with the issue of sorting items after inserting a new one. Default behavior when you insert a new ListViewItem at a given index, it will appear at the bottom of the list. I found this handy class to keep items sorted by index, which solved that problem:
class CompareByIndex : IComparer
{
private readonly ListView _listView;
public CompareByIndex(ListView listView)
{
this._listView = listView;
}
public int Compare(object x, object y)
{
int i = this._listView.Items.IndexOf((ListViewItem)x);
int j = this._listView.Items.IndexOf((ListViewItem)y);
return i - j;
}
}
And in the form load:
lvAllPages.ListViewItemSorter = new CompareByIndex(lvAllPages);
Obviously, that's a design decision. ImageList.Images is a ImageCollection and as such, it implements the IList interface.
Unfortunately, the Insert() method is allowed to throw a NotSupportedException. And that's what the list will do when used like a IList:
((IList)imageList.Images).Insert(5, new Bitmap(10,10));
System.NotSupportedException: 'Specified method is not supported.'
In order to have the images shown in a specific order, use the Add() method which takes the key:
imageList.Images.Add("1", new Bitmap(100,100));
That should also enable you to replace the image:
imageList.Images.RemoveByKey("1");
imageList.Images.Add("1", new Bitmap(200,200));
For that to work, you need to set the Sorting property:
listView1.Sorting = SortOrder.Ascending;
For storing additional information like path etc. use anotther data structure with the same key.
Here's the code:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
ImageList imageList = new ImageList();
Dictionary<string, Metadata> metadata = new Dictionary<string, Metadata>();
private string dir = #"H:\temp";
private void button1_Click(object sender, EventArgs e)
{
// You would set this in the designer, probably
listView1.Sorting = SortOrder.Ascending;
listView1.View = View.LargeIcon;
listView1.LargeImageList = imageList;
// Make sure we start from the beginning
listView1.Items.Clear();
imageList.Images.Clear();
metadata.Clear();
// Add items
for (int i = 0; i < 10; i++)
{
var filename = "1 ("+(i+1)+").png"; // Just strange names I have
var fullFileName = Path.Combine(dir, filename);
imageList.Images.Add(i.ToString(), Bitmap.FromFile(fullFileName));
metadata.Add(i.ToString(), new Metadata{Path = fullFileName});
listView1.Items.Add(i.ToString(), "Image " + i, i.ToString());
}
// Update view
listView1.Refresh();
listView1.Invalidate();
}
private void button2_Click(object sender, EventArgs e)
{
for (int i = 3; i < 6; i++)
{
var filename = "1 ("+(i+2)+").png";
var fullFileName = Path.Combine(dir, filename);
// Change image
imageList.Images.RemoveByKey(i.ToString());
imageList.Images.Add(i.ToString(), Bitmap.FromFile(fullFileName));
// Match metadata and image
metadata[i.ToString()] = new Metadata{Path = fullFileName};
}
listView1.Refresh();
}
private void listView1_SelectedIndexChanged(object sender, EventArgs e)
{
if (listView1.SelectedItems.Count > 0)
{
var key = listView1.SelectedItems[0].ImageKey;
label1.Text = metadata[key].Path;
}
else
{
label1.Text = "No image selected";
}
}
}
internal class Metadata
{
internal string Path;
}
I've been looking for a solution since this morning, and even after reading tons of other threads on this subject it doesn't work for me. Without further ados let's check this code sample:
// Create Dictionary, Keys = Ids, Values = Names
Dictionary<int, string> ff_names = new Dictionary<int, string>();
ff_names.Add(0, "Cloud");
ff_names.Add(1, "Barret");
ff_names.Add(2, "Tifa");
ff_names.Add(3, "Aerith");
ff_names.Add(4, "Red XIII");
// Populating ListView
foreach( KeyValuePair<int, string> dict in ff_names )
{
ListViewItem lvi = new ListViewItem(dict.Key.ToString());
lvi.SubItems.Add(dict.Value);
listView1.Items.Add(lvi);
}
// Test Item Selection
listView1.Focus();
listView1.Select();
listView1.Items[0].Focused = true;
listView1.Items[0].Selected = true;
string s = listView1.SelectedItems.Count.ToString();
label1.text = s; // sadly, it's equal to 0;
textBox1.Text = listView1.SelectedItems[0].SubItems[0].Text; // program will crash
Technically, I would like to selection an item of the ListView and display one of its element in a textbox. It works when I select an item manually, but when I try to select programmatically like shown above it doesn't want to select anything, the SelectedItems count is equal to zero...
Thank you for you help and hope someone can find a solution to what I'm missing!
Here you go. You'll have to make the event handler for listView1_SelectedIndexChanged.
public Form1() {
InitializeComponent();
listView1.View = View.Details;
listView1.Columns.Add("Key");
listView1.Columns.Add("Value");
LoadListView();
}
private void LoadListView() {
// Create Dictionary, Keys = Ids, Values = Names
Dictionary<int, string> ff_names = new Dictionary<int, string>();
ff_names.Add(0, "Cloud");
ff_names.Add(1, "Barret");
ff_names.Add(2, "Tifa");
ff_names.Add(3, "Aerith");
ff_names.Add(4, "Red XIII");
// Populating ListView
foreach (KeyValuePair<int, string> dict in ff_names) {
ListViewItem lvi = new ListViewItem(new string[] { dict.Key.ToString(), dict.Value });
listView1.Items.Add(lvi);
}
// Test Item Selection
listView1.Focus();
listView1.Select();
listView1.Items[0].Focused = true;
listView1.Items[0].Selected = true;
}
private void listView1_SelectedIndexChanged(object sender, EventArgs e) {
if (listView1.SelectedItems.Count > 0) {
label1.Text = (string)listView1.SelectedItems[0].Text; // sadly, it's equal to 0;
textBox1.Text = (string)listView1.SelectedItems[0].SubItems[1].Text;
}
}
I think drankin2112's answer is useful, but you say it doesn't work, so I complement it, hope this could be helpful to you.
To finish your work, you need to do three things as follow:
1.load data and fill in listview;
2.define the process method when listview's selected item changed;
3.give a test method to programmatically select different item, the you can see result.
my sample code is below:
public MainWindow()
{
InitializeComponent();
listView1.View = View.Details;
listView1.Columns.Add("Key");
listView1.Columns.Add("Value");
this.listView1.FullRowSelect = true;
//register the process event
this.listView1.SelectedIndexChanged += this.listView1_SelectedIndexChanged;
//load data
LoadListView();
//test item selection
ToSelectItem(0);
}
void ToSelectItem(int itemIndex)
{
if (itemIndex > listView1.Items.Count - 1)
return;
listView1.Focus();
listView1.Select();
listView1.Items[itemIndex].Focused = true;
listView1.Items[itemIndex].Selected = true;
}
private void LoadListView()
{
// Create Dictionary, Keys = Ids, Values = Names
Dictionary<int, string> ff_names = new Dictionary<int, string>();
ff_names.Add(0, "Cloud");
ff_names.Add(1, "Barret");
ff_names.Add(2, "Tifa");
ff_names.Add(3, "Aerith");
ff_names.Add(4, "Red XIII");
// Populating ListView
foreach (KeyValuePair<int, string> dict in ff_names)
{
ListViewItem lvi = new ListViewItem(new string[] { dict.Key.ToString(), dict.Value });
listView1.Items.Add(lvi);
}
}
private void listView1_SelectedIndexChanged(object sender, EventArgs e)
{
if (listView1.SelectedItems.Count > 0)
{
label1.Text = (string)listView1.SelectedItems[0].Text; // sadly, it's equal to 0;
textBox1.Text = (string)listView1.SelectedItems[0].SubItems[1].Text;
}
}
I have a list created by:
List<Song> SongList = new List<Song>();
Populated by a bunch of:
SongList.Add(new Song(songID, "Dirt", "Alice in Chains", "Rooster", "Rock", "02:32"));
The details of songs are populated into a ListBox by:
private void songTitle_TextChanged(object sender, EventArgs e)
{
i = 0;
for (; i < songTitle.Text.Length; i++)
{
songResultBox.Items.Clear();
var songResult = from song in SongList
where song.SongTitle != null && song.SongTitle.Length >= songTitle.Text.Length
&& songTitle.Text == song.SongTitle.Substring(0, i+1)
select new { sId = song.SongID, album = song.SongAlbum, artist = song.SongArtist, title = song.SongTitle,
genre = song.SongGenre, length = song.SongLength };
foreach (var item in songResult)
{
songResultBox.Items.Add(new Song(item.sId, item.album, item.artist, item.title, item.genre, item.length));
songResultBox.DisplayMember = "FullName";
songResultBox.ValueMember = "songID";
}
}
}
Question is: How would I create a button (or 4 in fact) that took the contents of the ListBox 'songResultBox' and sorted its contents by title, album, artist, genre etc.
Create the button, label it depending on what property you want to sort on, add a click event to the button, sort the items (hopefully you've maintained a list of them), then repopulate the listbox:
private bool descendingSongTitleSort = false;
private bool descendingArtistSort = false;
// Artist button clicked event
private void artistButtonClicked(object sender, EventArgs args)
{
Func<Song, IComparable> sortProp = (song => song.Artist);
sortListBox(songResultBox, descendingArtistSort, sortProp);
descendingSongTitleSort = false;
descendingArtistSort = !descendingArtistSort;
}
// Title button clicked event
private void titleButtonClicked(object sender, EventArgs args)
{
Func<Song, IComparable> sortProp = (song => song.Title);
sortListBox(songResultBox, descendingSongTitleSort, sortProp);
descendingSongTitleSort = !descendingSongTitleSort;
descendingArtistSort = false;
}
// Sorting function
private void sortListBox(
ListBox box,
bool descending,
Func<Song, IComparable> sortProperty)
{
List<Song> items = new List<Song>();
foreach (Object o in box.Items)
{
Song s = o as Song;
items.Add(s);
}
box.Items.Clear();
if(descending)
{
items = items.OrderByDescending(sortProperty).ToList();
}
else
{
items = items.OrderBy(sortProperty).ToList();
}
foreach(Song s in items)
{
box.Items.Add(s);
}
}
The descending bools aren't necessary if you don't want to worry about resorting in the opposite direction.