Display all values stored in a column to a label?

Question

I have a table called T_Score and the column called Team1, it has some stored values and I want these values to be added and displayed on a label.

This is the code which stores the values in the table:

private void Btn_LeaderB_Click(object sender, RoutedEventArgs e)
{
    this.NavigationService.Navigate(new LeaderBoard());

    SqlConnection conne = new SqlConnection(@"Data Source=LAPTOP-S2J1U9SJ\SQLEXPRESS;Initial Catalog=Unit4_IT;Integrated Security=True");

    conne.Open();
    string insertQuery = "insert into T_Score(Team1) " +
         "values(@Team1)";
    SqlCommand com = new SqlCommand(insertQuery, conne);

    com.Parameters.AddWithValue("@Team1", txt_score4_tm1.Text);

    com.ExecuteNonQuery();
    conne.Close();
}

This code stores the value that needs to be added with the previous value.

Answer 1

Use the following query select sum(Team1) from T_Score; and instead of cmd.ExecuteNonQuery(); use cmd.ExecuteScalar(); and use the return value of the method ExecuteScalar

https://learn.microsoft.com/en-us/dotnet/api/system.data.sqlclient.sqlcommand.executescalar

Like this:

private void WriteToLabel()
{    
    using (SqlConnection conne = new SqlConnection(@"Data Source=LAPTOP-S2J1U9SJ\SQLEXPRESS;Initial Catalog=Unit4_IT;Integrated Security=True"))
    {
        conne.Open();
        string selectQuery = "select sum(Team1) from T_Score;";
        using (SqlCommand com = new SqlCommand(selectQuery, conne))
            label1.Content = Convert.ToString(com.ExecuteScalar());
    }
}

The line

label1.Content = Convert.ToString(com.ExecuteScalar());

Will require a Label called label1 for it to work. It tries to write the result of Convert.ToString(com.ExecuteScalar()) into the Content property of said Label.

You can also use a TextBlock and than use the Text Property, so this line:

textBlock1.Text = Convert.ToString(com.ExecuteScalar());

Notice instead of calling conne.Close(); manually, I wrapped the SqlConnection conne into a using Statement, this should always be done with objects that inherit from IDisposable.

You can read about IDisposable and the using statement here:

• https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/using-statement
• https://learn.microsoft.com/en-us/dotnet/api/system.idisposable
• https://stackoverflow.com/a/61131/2598770

---

If you have the values already in a IEnumerable object eg. List<int> than you can just do the following

With a simple loop:

var myValues = new List<int>() { 1, 2, 3, 4, 5, 6 }; //<- list with temporary data
var sumOfValue = 0;
foreach (var myValue in myValues)
     sumOfValue += myValue;

With LINQ:

var myValues = new List<int>() { 1, 2, 3, 4, 5, 6 }; //<- list with temporary data
var sumOfValue = myValues.Sum();

If you don't have an IEnumerable of int but instead a class than your code will look like this

public class MyValue
{
    public int Value { get; set; }
    //other properties
}

var myValues = new List<MyValue>() 
               { 
                   new MyValue() { Value = 1 }, 
                   new MyValue() { Value = 2 }, 
                   new MyValue() { Value = 3 }, 
                   new MyValue() { Value = 4 }, 
                   new MyValue() { Value = 5 }, 
                   new MyValue() { Value = 6 }, 
               }; //<- list with temporary data

With a simple loop:

var sumOfValue = 0;
foreach (var myValue in myValues)
     sumOfValue += myValue.Value;

With LINQ:

var sumOfValue = myValues.Sum(x => x.Value);

In all those cases you will have to write sumOfValue into your Label or TextBlock like this

//Label
label1.Content = sumOfValue.ToString();
//or TextBlock
textBlock1.Text = sumOfValue.ToString();

---

To pass a value to a different page, all you would need to do is the following.

Search for your page in code behind eg. LeaderBoard. It should look something like this

public partial class LeaderBoard : Page
{
    //stuff...
}

Add a new Property to this class

public partial class LeaderBoard : Page
{
    public int MyProperty { get; set; }
    //stuff...
}

When you initialize the LeaderBoard eg. here

this.NavigationService.Navigate(new LeaderBoard());

Change the initialization to this:

this.NavigationService.Navigate(new LeaderBoard() { MyProperty = 7187, });

7187 is a random number this needs to be filled with what ever you need.

With this you have "transfered" data to LeaderBoard and the new property with its value can be accessed in LeaderBoard eg. there could be a method like this

public void Foo()
{
    textBlock1.Text = Convert.ToString(this.MyProperty);
}

The class would than look like this:

public partial class LeaderBoard : Page
{
    public int MyProperty { get; set; }
    //stuff...

    public void Foo()
    {
        textBlock1.Text = Convert.ToString(this.MyProperty);
    }
}

If you need to change the MyProperty from a different place while the LeaderBoard is open keep the reference you have created.

To keep the reference change this line

this.NavigationService.Navigate(new LeaderBoard() { MyProperty = 7187, });

To this

_leaderBoard = new LeaderBoard() { MyProperty = 7187, };
this.NavigationService.Navigate(_leaderBoard);

And create a Field in the outer scope like this

private LeaderBoard _leaderBoard; //<- needs to be outside the method

private void Btn_LeaderB_Click(object sender, RoutedEventArgs e)
{
    _leaderBoard = new LeaderBoard() { MyProperty = 7187, };
    this.NavigationService.Navigate(_leaderBoard);
}

If Btn_LeaderB_Click gets called multiple times but you only want to create 1 LeaderBoard you can do this:

private void Btn_LeaderB_Click(object sender, RoutedEventArgs e)
{
    if (_leaderBoard == null)
        _leaderBoard = new LeaderBoard() { MyProperty = 7187, };

    this.NavigationService.Navigate(_leaderBoard);
}

With that the _leaderBoard field will only get initialized once. If you want to increase the value MyProperty everytime the Btn_LeaderB_Click method gets called you can further extend it to this:

private void Btn_LeaderB_Click(object sender, RoutedEventArgs e)
{
    if (_leaderBoard == null)
        _leaderBoard = new LeaderBoard() { MyProperty = 7187, };
    else
        _leaderBoard.MyProperty += int.Parse(txt_score4_tm1.Text);

    this.NavigationService.Navigate(_leaderBoard);
}