Remove an item from listbox in WP8 - windows-phone-8

Question

I'm new to windows phone development. I'm trying to delete selected item from the list box. I've got dataclass
public class MyDataClass
{
public string MSG { get; set; }
public int Id { get; set; }
}
Then I try to delete the selected item (Button1_Click event)
MyDataClass item = MyDict.SelectedItem as MyDataClass;
ObservableCollection dataList = new ObservableCollection();
dataList.Remove(item);
The problem in creating the datalist in task, so it's no availble for the rest of the program, how to change this?
public async Task GETFROMDB()
{
int a = 1;
Database database = new Database(ApplicationData.Current.LocalFolder, "DictData.db");
await database.OpenAsync();
string query = "SELECT * FROM MyDICT";
Statement statement = await database.PrepareStatementAsync(query);
statement.EnableColumnsProperty();
ObservableCollection<MyDataClass> dataList = new ObservableCollection<MyDataClass>();
while (await statement.StepAsync())
{
rawData = string.Format(statement.Columns["value"]);
string[] sep = new string[] { "\r\n" }; //Splittng it with new line
string[] arrData = rawData.Split(sep, StringSplitOptions.RemoveEmptyEntries);
foreach (var d in arrData)
{
dataList.Add(new MyDataClass() { MSG = d, Id= a });
a++;
}
}
MyDict.ItemsSource = dataList;
}

Answer 1

Can you make binding to a dataList outside the Task and make dataList static or reference to it in a Task?
When creating a list:
static ObservableCollection<MyDataClass> dataList = new ObservableCollection<MyDataClass>();
MyDict.ItemsSource = dataList;
Then in Task:
public async Task GETFROMDB()
{
int a = 1;
Database database = new Database(ApplicationData.Current.LocalFolder, "DictData.db");
await database.OpenAsync();
string query = "SELECT * FROM MyDICT";
Statement statement = await database.PrepareStatementAsync(query);
statement.EnableColumnsProperty();
while (await statement.StepAsync())
{
rawData = string.Format(statement.Columns["value"]);
string[] sep = new string[] { "\r\n" }; //Splittng it with new line
string[] arrData = rawData.Split(sep, StringSplitOptions.RemoveEmptyEntries);
foreach (var d in arrData)
{
dataList.Add(new MyDataClass() { MSG = d, Id= a });
a++;
}
}
}
Then in Click:
MyDataClass item = MyDict.SelectedItem as MyDataClass;
dataList.Remove(item);
Or make it:
When creating a list:
ObservableCollection<MyDataClass> dataList = new ObservableCollection<MyDataClass>();
MyDict.ItemsSource = dataList;
Then in Task:
public async Task GETFROMDB(ObservableCollection<MyDataClass> dataList)
{
int a = 1;
Database database = new Database(ApplicationData.Current.LocalFolder, "DictData.db");
await database.OpenAsync();
string query = "SELECT * FROM MyDICT";
Statement statement = await database.PrepareStatementAsync(query);
statement.EnableColumnsProperty();
while (await statement.StepAsync())
{
rawData = string.Format(statement.Columns["value"]);
string[] sep = new string[] { "\r\n" }; //Splittng it with new line
string[] arrData = rawData.Split(sep, StringSplitOptions.RemoveEmptyEntries);
foreach (var d in arrData)
{
dataList.Add(new MyDataClass() { MSG = d, Id= a });
a++;
}
}
}
Then in Click:
MyDataClass item = MyDict.SelectedItem as MyDataClass;
dataList.Remove(item);
Of course you need to wait until the Task is finished.

Answer 2

you appear to be trying to remove the item from a brand new collection - try instead to remove it from the one that your listbox is data bound to.

Answer 3

Try using the button data context
like this
in your click handler
private void ButtonClick(object sender, RoutedEventArgs e)
{
Button btn = sender as Button;
if (btn != null)
{
MyDataClass item = btn.DataContext as MyDataClass;
dataList.Remove(item);
}
}