How to get a particular column from table and display in in label and not in the list in sqlite database in mvvm model

Gbenga Banuso Odumosu 40

In MVVM model using async connection, I want to retrieve just one column from my async table to a label not to list. all sample I am seeing put all column in the list . I want only one mesa1 column to be displayed in a label.text.

public async Task

Gbenga Banuso Odumosu 40

using SQLite;

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using Vase.Model;

namespace Vase.Model

{

[Table("serviceData")]

public class ServiceData

{

   

    [PrimaryKey, AutoIncrement]

    public int Id { get; set; }

    [MaxLength(250)]

    public string imagePath { get; set; }

    public string name { get; set; }

    public string nin { get; set; }

   

    public string typeofservice { get; set; }

    public string area { get; set; }

    public string state { get; set; }

    public string city { get; set; }

    public string gsm { get; set; }

    public string servicerate { get; set; }

    public double long1 { get; set; }

    public double lat1 { get; set; }

   

    public string mesa1 { get; set; }

    public string mesa2 { get; set; }

    public string mesa3 { get; set; }

    public Int16 total1 { get; set; }

    public Int32 RegNo { get; set; }

   

}

}

This is my Resipotry

public async Task<ServiceData> GetById()

{

// if (File.Exists("servicereg.txt"))

 //{

     var path = FileSystem.Current.AppDataDirectory;

     var fullpath = Path.Combine(path, "servicereg.txt");

     var fullpath2 = Path.Combine(path, "serviceregNo.txt");

     //mylabel.Text = File.ReadAllText(fullpath);

     Regno1 = File.ReadAllText(fullpath2);

     Regno = Int32.Parse(Regno1);

 //}

     await Init();

 // return await conn.Table<ServiceData>().ToListAsync();

 return await conn.Table<ServiceData>().Where(s => s.RegNo == Regno).FirstOrDefaultAsync();

and this my service page

protected override async void OnAppearing()

{

 base.OnAppearing();

 ServiceData serviceData =  await App.PersonRepo.GetById();

 Myname.Text = serviceData.name;

}

When I use Myname.Text =serviceData.name, it will not bring anything out but when it is

Myname.Text =serviceData.RegNo or Myname.Text =serviceData.Id then it will come out with the result but any string variable will bring any result

What I am doing wrongly please

Gbenga Banuso Odumosu 40 Reputation points

2024-06-11T11:32:34.5066667+00:00
Thanks so much for your guidance

truly , the value of a is null when i trace as adviced while the value of Id and RegNo are true

however if I didnt use the .while statement to query the table, and ask it to use list to display the result as in Resipory.cs

await Init();

return await conn.Table<ServiceData>().ToListAsync();

// return await conn.Table<ServiceData>().Where(s => s.RegNo == Regno).FirstOrDefaultAsync();

And on my page

base.OnAppearing();

List<ServiceData> people = await App.PersonRepo.GetById();

peopleList.ItemsSource = people;

It will display all the data, which shows that all the data was recoded on the table

Is anything wrong in my WHILE statement? and please can I use select statement and discard this method? and How can i use SELECT statement on this method.

Thanks I appreciate your time and knowledge
Leon Lu (Shanghai Wicresoft Co,.Ltd.) 76,551 Reputation points Microsoft Vendor

2024-06-12T06:20:47.62+00:00
Thanks so much for your guidance truly , the value of a is null when i trace as adviced while the value of Id and RegNo are tr

Thanks for your update. I convert my comment to answer. This issue is solved, please accept it as answer, it will help others who have similar issue.

Is anything wrong in my WHILE statement? and please can I use select statement and discard this method? and How can i use SELECT statement on this method.

If you have gotten List<ServiceData> people = await App.PersonRepo.GetById();, you can use where like following code. If you still cannot get the value, please open a new thread in Q&A and add your static test data, layout code and reproduce steps.

int Regno = 1; ServiceData service = people.Where<ServiceData>(t => t.RegNo == Regno).FirstOrDefault(); Myname.Text =service.name

1 answer

Leon Lu (Shanghai Wicresoft Co,.Ltd.) 76,551 Reputation points Microsoft Vendor

2024-06-10T01:32:40.6633333+00:00
Can you share your code about ServiceData? If the ServiceData.cs is like following code.

public class ServiceData { public string Name { get; set; } public int RegNo { get; set; } }

If you want to get the column called Name and set it to the label. Please use following code to get it.

ServiceData serviceData=await GetItem(regno); myid.Text=serviceData.Name;

If not, please share your code about ServiceData.cs.
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1 person found this answer helpful.
Leon Lu (Shanghai Wicresoft Co,.Ltd.) 76,551 Reputation points Microsoft Vendor

2024-06-11T09:45:47.67+00:00

You can add a breakpoint in this line ServiceData serviceData = await App.PersonRepo.GetById();, check the value of serviceData properties, if these value of properties is empty, if value is empty, this column is empty in this table of SqliteDB. You can try to insert a test value to the DB and get it.

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Leon Lu (Shanghai Wicresoft Co,.Ltd.) 76,551 Reputation points Microsoft Vendor

2024-06-19T07:30:07.51+00:00

Gbenga Banuso Odumosu May I know if you have got any chance to check my answer? I am glad to help if you have any other questions.
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