I'm coding a Phone book. It's fully coded and I'm really happy with the results (first ever finished application!). It's a phone book coded in WPF, and I'm using a DataGrid to simply store the values of the people added. The thing is I can add people and it's all smooth until I shut it down and all stored data is lost. This always happens with all the smaller projects I've done but alot of them were just application that could run a few numbers through an equation and give me an answer and I didn't require the data I had gotten. But with my phone book I want my user to open it and use it over and over again. Thank you in advance :D
EDIT: I forgot to mention that my DataGrid isn't binded to an SQL database so i cant update it on opening after a close.
There are Closing and Closed events in every Window, to begin with.
As mentioned in the comments, your question is a little vague, but here's a worked example for you using binary serialization to create a file with your data in isolated storage (see MSDN Isolated Storage)
I assume you have some kind of backing class for your DataGrid so in this case, I have created a class called Contact. Note the [Serializable] attribute:
[Serializable]
public class Contact {
public String Name { get; set; }
public String Number { get; set; }
public Contact(String name, String number) {
Name = name;
Number = number;
}
}
I then have a list of these:
private List<Contact> contacts;
You can override the OnClosing method of your Window and then save your data down to a file:
protected override void OnClosing(CancelEventArgs e) {
base.OnClosing(e);
using (IsolatedStorageFile isoStore = IsolatedStorageFile.GetStore(IsolatedStorageScope.User | IsolatedStorageScope.Domain | IsolatedStorageScope.Assembly, null, null)) {
if (isoStore.FileExists("contacts.dat")) {
// We already have an old one, delete it
isoStore.DeleteFile("contacts.dat");
}
using (IsolatedStorageFileStream fs = isoStore.CreateFile("contacts.dat")) {
BinaryFormatter bf = new BinaryFormatter();
bf.Serialize(fs, contacts);
}
}
}
And finally after you have done whatever initialisation you need to do, you can look for this file and restore your contacts if they are there as below. Note I have added some dummy entries if there is no backup:
using (IsolatedStorageFile isoStore = IsolatedStorageFile.GetStore(IsolatedStorageScope.User | IsolatedStorageScope.Domain | IsolatedStorageScope.Assembly, null, null)) {
if (isoStore.FileExists("contacts.dat")) {
IsolatedStorageFileStream fs = isoStore.OpenFile("contacts.dat", System.IO.FileMode.Open);
BinaryFormatter bf = new BinaryFormatter();
contacts = (List<Contact>) bf.Deserialize(fs);
}else {
// We don't have a backup file, create some dummy entries
contacts = new List<Contact>();
contacts.Add(new Contact("John Smith", "1234567"));
contacts.Add(new Contact("Emma Brown", "7654321"));
}
}
MyDataGrid.ItemsSource = contacts;
The ItemsSource of your DataGrid should be set or bound to an IEnumerable<T>. To save the data to a file on disk you could then serialize all items in this IEnumerable<T> to a file. You then deserialize it back again when the application starts. The following sample code should give you the idea.
MainWindow.xaml:
<DataGrid x:Name="dataGrid" AutoGenerateColumns="False">
<DataGrid.Columns>
<DataGridTextColumn Binding="{Binding Name}" />
<DataGridTextColumn Binding="{Binding Number}" />
</DataGrid.Columns>
</DataGrid>
MainWindow.xaml.cs:
public partial class MainWindow : Window
{
private const string _fileName = "phonebook.txt";
public MainWindow()
{
InitializeComponent();
this.Loaded += (s, e) =>
{
//create a List<Item> that contains the data from the file on a background thread
Task.Run(() => LoadData()).ContinueWith(task =>
{
//...and set the ItemsSource property of the DataGrid to the returned List<Item>
dataGrid.ItemsSource = task.Result;
}, System.Threading.CancellationToken.None, TaskContinuationOptions.None, TaskScheduler.FromCurrentSynchronizationContext());
};
this.Closing += (s, e) => SaveData();
}
public List<Item> LoadData()
{
List<Item> items = new List<Item>();
if (System.IO.File.Exists(_fileName))
{
string[] lines = System.IO.File.ReadAllLines(_fileName);
foreach (string line in lines)
{
string[] columns = line.Split(new char[] { ';' }, StringSplitOptions.RemoveEmptyEntries);
if (columns.Length == 2)
{
items.Add(new Item()
{
Name = columns[0],
Number = columns[1]
});
}
}
}
else
{
//populate the DataGrid with some default data...
items.Add(new Item { Name = "Name1", Number = "000-111" });
items.Add(new Item { Name = "Name2", Number = "111-222" });
}
return items;
}
private void SaveData()
{
IEnumerable<Item> items = dataGrid.ItemsSource as IEnumerable<Item>;
if (items != null)
{
using (System.IO.StreamWriter sw = new System.IO.StreamWriter(_fileName))
foreach (Item item in items)
sw.WriteLine($"{item.Name};{item.Number}");
}
}
}
Item.cs:
public class Item
{
public string Name { get; set; }
public string Number { get; set; }
}
The "phonebook.txt" file will be saved in the output directory - typically c:\YourProjectFolder\bin\Debug or \bin\Release when running your application from Visual Studio - of your executable (.exe) unless you change the value of the _fileName field.
Related
I have an issue with binding ComboBox ItemsSource with a list. I read workplaces from csv file. It can't see the Workplaces list. Please, tell me what is wrong.
xaml:
<ComboBox Grid.Column="1" Grid.Row="9" Height="25" Margin="0,18,0,0" ItemsSource="{Binding Workplaces}">
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding title}" />
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
xaml.cs:
public partial class MainWindow : Window
{
private BindableCollection<WorkplaceInfo> Workplaces { get; set; }
public MainWindow()
{
InitializeComponent();
Workplaces = new BindableCollection<WorkplaceInfo>(GetWorkplaces());
}
private List<WorkplaceInfo> GetWorkplaces()
{
List<WorkplaceInfo> workplaces = new List<WorkplaceInfo>();
using (var streamReader = new StreamReader("Workplaces.csv"))
{
using (var csvReader = new CsvReader(streamReader, CultureInfo.InvariantCulture))
{
//csvReader.Context.RegisterClassMap<WorkplaceInfoClassMap>();
var workplaceInfoList = csvReader.GetRecords<dynamic>().ToList();
foreach (var wi in workplaceInfoList)
{
workplaces.Add(new WorkplaceInfo(wi.title, wi.member_of.Split(";")));
}
}
}
return workplaces;
}
}
WorkplaceInfo class:
class WorkplaceInfo
{
public String title { get; }
public String[] memberOfList { get; }
public WorkplaceInfo(string title, string[] memberOfList)
{
this.title = title;
this.memberOfList = memberOfList;
}
}
Here is your code optimized to work:
public ObservableCollection<WorkplaceInfo> Workplaces { get; set; }
public MainWindow()
{
this.DataContext = this;
Workplaces = new ObservableCollection<WorkplaceInfo>(GetWorkplaces());
InitializeComponent();
}
private List<WorkplaceInfo> GetWorkplaces()
{
List<WorkplaceInfo> workplaces = new List<WorkplaceInfo>();
try
{
using (var streamReader = new StreamReader("Workplaces.csv"))
{
using (var csvReader = new CsvReader(streamReader, CultureInfo.CurrentCulture))
{
//csvReader.Context.RegisterClassMap<WorkplaceInfoClassMap>();
var workplaceInfoList = csvReader.GetRecords<dynamic>().ToList();
foreach (var wi in workplaceInfoList)
{
var titl = wi.title;
workplaces.Add(new WorkplaceInfo(wi.title, new List<string>() { wi.member_of }.ToArray()));
}
}
}
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}
return workplaces;
}
So the changes needed in your code are:
Set your Workplaces collection to public ObservableCollection
Add DataContext binding
Read in the Date and create the collection before the main window is initialized (other way round the UI will not detect the change in you object unless you implement INotifyPropertyChanged event)
p.s. I don't know the structure of your csv file so I made my small demo like (Workplaces.csv) and adopted the parser. You can keep your parser if it matches your csv file structrue.:
title;member_of
London;First
Amsterdam;Second
And my warm recommendation is to use try-catch block always when handling files and when working with anything what is external to your application.
Best regards.
I am trying to populate a collection view from a ViewModel, however when I try to bind the data to the collection view, the ViewModel is null.
xaml.cs file
ObservableCollection<ReportsClass> newKidList = new ObservableCollection<ReportsClass>();
public ReportsViewModel viewmodel { get; set; }
public ReportsPage()
{
InitializeComponent();
viewmodel = new ReportsViewModel();
this.BindingContext = viewmodel;
PreviousDateRange.CornerRadius = 20;
NextDateRange.CornerRadius = 20;
DateTime firstDate = currentDate.StartOfWeek(DayOfWeek.Sunday);
DateTime secondDate = currentDate.AddDays(7).StartOfWeek(DayOfWeek.Saturday);
DateRange.Text = firstDate.ToString("MMMM d") + " - " + secondDate.ToString("MMMM d");
Kids.SetBinding(ItemsView.ItemsSourceProperty, nameof(viewmodel.kids));
}
Here is my view model
public class ReportsViewModel
{
public ObservableCollection<ReportsClass> kids { get; set; }
FirebaseStorageHelper firebaseStorageHelper = new FirebaseStorageHelper();
WebServiceClass webServiceClass = new WebServiceClass();
DateTime currentDate = DateTime.Now;
public ReportsViewModel()
{
GetKids();
}
public async void GetKids()
{
var parentId = await SecureStorage.GetAsync("parentid");
kids = await webServiceClass.Reports(Convert.ToInt32(parentId), currentDate.StartOfWeek(DayOfWeek.Sunday), currentDate.AddDays(7).StartOfWeek(DayOfWeek.Saturday));
}
}
And here is the method that gets the data for the view model
public async Task<ObservableCollection<ReportsClass>> Reports(int parentid, DateTime startDate, DateTime endDate)
{
var content = new FormUrlEncodedContent(new[]
{
new KeyValuePair<string, string>("parentid", parentid.ToString()),
new KeyValuePair<string, string>("startDate", startDate.ToString("yyyy-MM-dd H:mm:ss")),
new KeyValuePair<string, string>("endDate", endDate.ToString("yyyy-MM-dd"))
});
var response = await client.PostAsync(string.Format("https://example.com/api/index.php?action=reports"), content);
var responseString = await response.Content.ReadAsStringAsync();
ObservableCollection<ReportsClass> items = JsonConvert.DeserializeObject<ObservableCollection<ReportsClass>>(responseString);
return items;
}
What am I doing wrong? The purpose of me doing it this way is so I can update an item in the collectionview
Here is my ReportsClass
public class ReportsClass
{
public ReportsClass(string firstName)
{
first_name = firstName;
}
public string first_name { get; set; }
}
OPTION A:
Fix the syntax of Kids.SetBinding, to not get null. Refer to the CLASS ReportsViewModel, not to the INSTANCE viewmodel:
Kids.SetBinding(ItemsView.ItemsSourceProperty, nameof(ReportsViewModel.kids));
The kids still won't appear in list. To fix, kids needs OnPropertyChanged:
public ObservableCollection<ItemModel> kids {
get => _kids;
set {
_kids = value;
OnPropertyChanged();
}
}
private ObservableCollection<ItemModel> _kids;
See the other code in Option B. Adapt as desired.
When you need XAML to see a DYNAMIC change, you need OnPropertyChanged. This is an implementation of INotifyPropertyChanged. Add this call to properties (that XAML binds to) of ReportsClass:
// Inheriting from `BindableObject` is one way to obtain OnPropertyChanged method.
public class ReportsClass : Xamarin.Forms.BindableObject
{
public ReportsClass(string firstName)
{
first_name = firstName;
}
public string first_name {
get => _first_name;
set {
_first_name = value;
// This tells XAML there was a change.
// Makes "{Binding first_name}" work dynamically.
OnPropertyChanged();
}
}
private string _first_name;
}
OPTION B:
Didn't find an answer anywhere that does everything correctly, so here is a complete sample, for future reference:
Remove Kids.SetBinding(...). (It can be fixed as shown in OPTION A, but its easier to get it correct in XAML, so below I show it in XAML.)
Bindings from Page to VM. See xaml below.
Create ObservableCollection with setter that does OnPropertyChanged. This informs XAML when the list is ready, so page updates. (This is an implementation of INotifyPropertyChanged, as Jason mentioned.)
Use Device.BeginInvokeOnMainThread(async () to create an async context, that is queued to run after constructor returns. (This fixes the issue Jason mentioned, which is that a constructor isn't an async context, so should not DIRECTLY call an async method such as QueryItemsAsync, or your GetKids.) This is more reliable.
PageWithQueryData.xaml:
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="TestXFUWP.PageWithQueryData">
<ContentPage.Content>
<StackLayout>
<CollectionView ItemsSource="{Binding Items}">
<CollectionView.ItemTemplate>
<DataTemplate>
<StackLayout>
<Label Text="{Binding Name}" />
</StackLayout>
</DataTemplate>
</CollectionView.ItemTemplate>
<CollectionView.EmptyView>
<Grid>
<Label Text="Loading ..." FontSize="24" TextColor="Blue" BackgroundColor="LightBlue" HorizontalTextAlignment="Center" VerticalTextAlignment="Center" />
</Grid>
</CollectionView.EmptyView>
</CollectionView>
</StackLayout>
</ContentPage.Content>
</ContentPage>
PageWithQueryData.xaml.cs:
public partial class PageWithQueryData : ContentPage
{
public PageWithQueryData()
{
InitializeComponent();
// ... other initialization work here ...
// BUT remove `Kids.Binding(...);` line. See XAML: `ItemsSource="{Binding Items}"`.
BindingContext = new VMWithQueryData();
}
}
VMWithQueryData.cs:
class VMWithQueryData : Xamarin.Forms.BindableObject
{
public VMWithQueryData()
{
// Start an async task to query.
Xamarin.Forms.Device.BeginInvokeOnMainThread(async () => {
await QueryItemsAsync();
});
// Alternative implementation: Start a background task to query.
//QueryItemsInBackground();
}
public ObservableCollection<ItemModel> Items {
get => _items;
set {
_items = value;
OnPropertyChanged();
}
}
private ObservableCollection<ItemModel> _items;
private async Task QueryItemsAsync()
{
var names = new List<string> { "One", "Two", "Three" };
bool queryOneAtATime = false;// true;
if (queryOneAtATime) {
// Show each item as it is available.
Items = new ObservableCollection<ItemModel>();
foreach (var name in names) {
// Simulate slow query - replace with query that returns one item.
await Task.Delay(1000);
Items.Add(new ItemModel(name));
}
} else {
// Load all the items, then show them.
// Simulate slow query - replace with query that returns all data.
await Task.Delay(3000);
var items = new ObservableCollection<ItemModel>();
foreach (var name in names) {
items.Add(new ItemModel(name));
}
Items = items;
}
}
// Alternative implementation, using a background thread.
private void QueryItemsInBackground()
{
Task.Run(() => {
var names = new List<string> { "One", "Two", "Three" };
bool queryOneAtATime = false;// true;
if (queryOneAtATime) {
// Show each item as it is available.
Items = new ObservableCollection<ItemModel>();
foreach (var name in names) {
// Simulate slow query - replace with query that returns one item.
System.Threading.Thread.Sleep(1000);
Items.Add(new ItemModel(name));
}
} else {
// Load all the items, then show them.
// Simulate slow query - replace with query that returns all data.
System.Threading.Thread.Sleep(3000);
var items = new ObservableCollection<ItemModel>();
foreach (var name in names) {
items.Add(new ItemModel(name));
}
Items = items;
}
});
}
}
ItemModel.cs:
public class ItemModel
{
public ItemModel(string name)
{
Name = name;
}
public string Name { get; set; }
}
This also demonstrates <CollectionView.EmptyView> to display a message to user, while the data is being queried.
For completeness, I've included an alternative QueryItemsInBackground, that uses a background thread instead of an async method. Either approach works well.
Notice inheritance from Xamarin.Forms.BindableObject. This is one way to get an implementation of INotifyPropertyChanged. You can use any other MVVM library or technique.
Move this line of code to the end of your constructor
this.BindingContext = viewmodel;
im completly new to programing,
im trying to create something like a manga organizing tool in windows forms, but im getting stuck in populating a listbox with data from a deserialized json string, it currently is only displaying boolean values correctly all other values are "0" even strings.
i have a button to do this:
using (OpenFileDialog openFileDialog = new OpenFileDialog() { Filter = "Json Files|*.json", ValidateNames = true, Multiselect = false })
{
if (openFileDialog.ShowDialog() == DialogResult.OK)
{
var fileStream = openFileDialog.OpenFile();
using (StreamReader sr = new StreamReader(fileStream))
{
string fileContent = sr.ReadToEnd();
ComicList comics = JsonConvert.DeserializeObject<ComicList>(fileContent);
Manga_listBox.DataSource = DisplayComic.FullList;
//ignore this little bit it's just so i can see what's happening
label1.Text = Convert.ToString(comics.Comics.Count);
label1.Text = Convert.ToString(DisplayComic.FullList);
}
}
}
and i have the following classes like so:
public class Comic
{
private string Manga;
private int Chapters;
private bool isFinished;
private int LastReadCH;
public string Manga1 { get => Manga; set => Manga = value; }
public int Chapters1 { get => Chapters; set => Chapters = value; }
public bool IsFinished { get => isFinished; set => isFinished = value; }
public int LastReadCH1 { get => LastReadCH; set => LastReadCH = value; }
public Comic(Comic asd)
{
this.Manga = Manga1;
this.Chapters = Chapters1;
this.IsFinished = IsFinished;
this.LastReadCH = LastReadCH1;
}
public override string ToString()
{
return string.Format("{0}, {1}, {2}, {3}",
this.Manga, this.Chapters, this.IsFinished, this.LastReadCH);
}
}
and
public class ComicList
{
private List<Comic> comics;
public List<Comic> Comics { get => comics; set => comics = value; }
}
and
public class DisplayComic
{
static DisplayComic()
{
using (OpenFileDialog openFileDialog = new OpenFileDialog() { Filter = "Json Files|*.json", ValidateNames = true, Multiselect = false })
{
if (openFileDialog.ShowDialog() == DialogResult.OK)
{
var fileStream = openFileDialog.OpenFile();
using (StreamReader sr = new StreamReader(fileStream))
{
string fileContent = sr.ReadToEnd();
ComicList comics = JsonConvert.DeserializeObject<ComicList>(fileContent);
FullList = comics.Comics;
}
}
}
}
private static List<Comic> fullList;
public static List<Comic> FullList { get => fullList; set => fullList = value; }
public static List<Comic> GetComcis()
{
return FullList;
}
}
code is probably quite messy, then again I'm completely new and have been following all kind of information online, also for some reason, the open dialog windows is opening twice I don't understand why.
here is the json file I'm using:
{
"Comics": [
{
"Manga": "MangaNumber1",
"Chapters": 85,
"isFinished": true,
"LastReadCH": 85
},
{
"Manga": "MangaNumber2",
"Chapters": 112,
"isFinished": true,
"LastReadCH": 112
},
{
"Manga": "MangaNumber3",
"Chapters": 117,
"isFinished": true,
"LastReadCH": 117
},
{
"Manga": "MangaNumber4",
"Chapters": 74,
"isFinished": true,
"LastReadCH": 74
}
]
}
I've tried pretty much anyone with my "expertise" could, changing all kind of variable names and so on, would really appreciate some help.
here's a screenshot of the problem:
as you can see only the boolean values are actually correct, otherwise they'd be false, all other values though...
EDIT:
the result im hopping for is to populate the listbox with the manga names, (thank you #beeker for that property thing) and once i select said manga then i want to create some other objects such as labels and text boxes to view and edit the values of the chapters etc, also i would like to be able to see what is being parsed by the json file how ever when i do this:
label1.Text = Convert.ToString(comics);
i get the label with the text "Manga_Organizer_2.ComicList"
By the way when i say im new, i mean i only ever did stuff with console apps using only "if" functions this whole parsing json, openfiledialog, and even classes usage is completly new. I also have no background in programing with any other language c# is the first and im loving it even though having terrible difficulties :)
Answer/Update:
All is good now :)
all i had to do was set
DisplayComic.FullList = comics.Comics;
in the openfiledialog right before setting the datasource for the listbox.
In the end it looks like this:
string fileContent = sr.ReadToEnd();
ComicList comics = JsonConvert.DeserializeObject<ComicList>(fileContent);
DisplayComic.FullList = comics.Comics;
Manga_listBox.DataSource = DisplayComic.FullList;
Manga_listBox.DisplayMember = "manga";
also removed the encapsulations alltogether in the comic class, in the end it looks like this:
public class Comic
{
public string Manga { get; set; }
public double Chapters { get; set; }
public bool IsFinished { get; set; }
public double LastReadCH { get; set; }
public string StartedOn { get; set; }
public string FinishedOn { get; set; }
}
and also the displaycomic class looks like this:
public class DisplayComic
{
public static List<Comic> FullList { get; set; }
public static List<Comic> GetComcis()
{
return FullList;
}
}
Also, after all this trouble came even more, i could deserialize the json, parse it to a string and then to a list, load, save and edit it and i also managed to serialize it back together, and with a savefiledialog create a file for it, however when i did, i would be unable to re-deserialize it once again, something about the json had changed (from object to array or vice versa), aside from that i also had problems with datetime stuff, couldn't load it correctly from a string and so on, anyway after a bunch of mishaps, and litteraly 17hours of looking at code with a puzzled face i finnaly finished my app :D!
It does all i want it to, load a json, save and edit it, put it back together, add and remove from it, and i learned a bunch from all this trouble, thank you all for helping, thanks to you guys learned how to set stuff to display on listboxes, and also very importantly "somewhat" learned how to debug code.
Thanks.
Try setting the listbox "DisplayMember" property so that the control knows which property of the class you want to see. Something like this...
Manga_listBox.DataSource = DisplayComic.FullList;
Manga_listBox.DisplayMember = "Manga";
Ref:
https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.listcontrol.displaymember?view=netframework-4.8
Answer:
i removed that whole openfiledialog in the display comic class, renamed the encapsulations in the Comic class and done :D, now the openfiledialog only opens once and the values from the json are being correctly parsed to the comics list, thus enabling me to use them however i want, thank you, you pushed me in the right direction with the idea to learn debug stuff :D.
Now all that's left is learn how to create objects by selecting the different lines from the listbox, another challenge awaits this newcomer.
Step 1: I have created a C# application called : Student details
Step 2: Added four TextBoxes and named them as :
Image below to refer:
Studentname.Text
StudentSurname.Text
StudentCity.Text
StudentState.Text
DATA INSIDE CSV FILE
vikas,gadhi,mumbai,maharashtra
prem,yogi,kolkata,maha
roja,goal,orissa,oya
ram,kala,goa,barka
Issue is How do I fetch all the data(surname,city,state) of user prem into above textboxes studentsurname,studentcity,studentstate from csv file when I search the name in textbox 1 => studentname.Text as prem
Below is the Code where I am stuck at return null and code inside Load_Script_Click
void Connection_fetch_details(String searchName)
{
var strLines = File.ReadLines(filePath);
foreach (var line in strLines)
{
if (line.Split(',')[0].Equals(searchName))
{
Connection_fetch_details cd = new Connection_fetch_details()
{
username = line.Split(',')[1]
};
}
}
return;
}
private void Load_Script_Click(object sender, EventArgs e)
{
// load script is button
String con_env = textenv.Text.ToString();
//Address Address = GetAddress("vikas");
//textsurname.text = Address.Surname
Connection_fetch_details cd = Connection_fetch_details(con_env);
textusername.Text = cd.username;
}
==============================================================
Class file name : Address.class
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace DDL_SCRIPT_GENERATOR
{
public class Connection_fetch_details
{
public string username { get; set; }
}
}
The main problem is that your method is void, which means it doesn't return any value. So even though you may be finding a match, and creating a Connection_fetch_details object, you aren't returning that result back to the calling method.
This will fix that problem:
Connection_fetch_details Connection_fetch_details(String searchName)
{
var strLines = File.ReadLines(filePath);
foreach (var line in strLines)
{
if (line.Split(',')[0].Equals(searchName))
{
Connection_fetch_details cd = new Connection_fetch_details()
{
username = line.Split(',')[1]
};
return cd; //return the object containing the matched username
}
}
return null;
}
Now it will return a Connection_fetch_details object if there is a match, or null if there is no match.
Next, you asked about returning all the fields, not just one. For that you would need to
a) add more properties to your object
b) add more code to populate those properties from the CSV
c) add code to populate the textboxes with the results from the object.
I'm also going to rename "username" to something more relevant, since none of the field names you described in the question match that. I'm also going to rename your class to "Student", and rename your search method, for the same reason.
Here's an example:
Student searchStudent(String searchName)
{
var strLines = File.ReadLines(filePath);
foreach (var line in strLines)
{
var split = line.Split(',');
if (split[0].Equals(searchName))
{
Student s = new Student()
{
firstname = searchName,
surname = split[1],
city = split[2],
state = split[3]
};
return s; //return the object containing the matched name
}
}
return null;
}
private void Load_Script_Click(object sender, EventArgs e)
{
// load script is button
String con_env = textenv.Text.ToString();
//Address Address = GetAddress("vikas");
//textsurname.text = Address.Surname
Student st = searchStudent(con_env);
textsurname.Text = st.surname;
txtcity.Text = st.city;
txtstate.Text = st.state;
}
namespace DDL_SCRIPT_GENERATOR
{
public class Student
{
public string firstname { get; set; }
public string surname { get; set; }
public string city { get; set; }
public string state { get; set; }
}
}
To accomplish your goal you have to further separate your problem in more granular steps and also distinguish between what you show in your UI and what informations you hold in the background in which format.
Create a class with the desired properties
public class Student { public string Name { get; set; } ... }
Learn how to read a csv file into such an object by using an existing library like CsvHelper or CsvReader.
When you have something like List<Student> from this part. Learn how you can visualize such a thing by using some Binding (also depends on the visualization you use Winforms, WPF, etc.).
Depending on the visualization component it already supports filtering or you need to filter by yourself by using e.g. LINQ to get the matching elements students.Where(student => student.Name.StartsWith(search)).
So far a lot of smaller problems which is simply to much to answer in a single one. Please try to break down your problems into smaller ones and search for their solutions. If you get stuck, ask a new question. That's all I can do for you now.
I have searched Google for a simple solution to this but no luck. I have a standard WPF combo box which I would simply like to be able to filter the list displayed according to the first 2 or 3 letters a users types when the combo box has focus. I tried some coding including some lamba expressions but the error "System.NotSupportedException" keeps getting thrown on the line where "combobox.Items.Filter" is specified. I'm not using MVVM and would just like this simple functionality available for the user. Please help! P.S. IsEditable, IsTextSearchEnabled and StaysOpenOnEdit properties are set to true but the desired functionality is not yet achieved.
I have developed a sample application. I have used string as record item, you can do it using your own entity. Backspace also works properly.
public class FilterViewModel
{
public IEnumerable<string> DataSource { get; set; }
public FilterViewModel()
{
DataSource = new[] { "india", "usa", "uk", "indonesia" };
}
}
public partial class WinFilter : Window
{
public WinFilter()
{
InitializeComponent();
FilterViewModel vm = new FilterViewModel();
this.DataContext = vm;
}
private void Cmb_KeyUp(object sender, KeyEventArgs e)
{
CollectionView itemsViewOriginal = (CollectionView)CollectionViewSource.GetDefaultView(Cmb.ItemsSource);
itemsViewOriginal.Filter = ((o) =>
{
if (String.IsNullOrEmpty(Cmb.Text)) return true;
else
{
if (((string)o).Contains(Cmb.Text)) return true;
else return false;
}
});
itemsViewOriginal.Refresh();
// if datasource is a DataView, then apply RowFilter as below and replace above logic with below one
/*
DataView view = (DataView) Cmb.ItemsSource;
view.RowFilter = ("Name like '*" + Cmb.Text + "*'");
*/
}
}
XAML
<ComboBox x:Name="Cmb"
IsTextSearchEnabled="False"
IsEditable="True"
ItemsSource="{Binding DataSource}"
Width="120"
IsDropDownOpen="True"
StaysOpenOnEdit="True"
KeyUp="Cmb_KeyUp" />
I think the CollectionView is what you are looking for.
public ObservableCollection<NdfClassViewModel> Classes
{
get { return _classes; }
}
public ICollectionView ClassesCollectionView
{
get
{
if (_classesCollectionView == null)
{
BuildClassesCollectionView();
}
return _classesCollectionView;
}
}
private void BuildClassesCollectionView()
{
_classesCollectionView = CollectionViewSource.GetDefaultView(Classes);
_classesCollectionView.Filter = FilterClasses;
OnPropertyChanged(() => ClassesCollectionView);
}
public bool FilterClasses(object o)
{
var clas = o as NdfClassViewModel;
// return true if object should be in list with applied filter, return flase if not
}
You wanna use the "ClassesCollectionView" as your ItemsSource for your Combobox