如何在Xamarin.Forms中设置选择器的选定项？

Question

I have a picker with that gets the customer outlet. I want to update the what I saved from my database.

Here is my app logic:
1. The user will select a customer outlet
2. The user will save the selected outlet
3. The user will have an option to update what the user selected 4. Upon loading of the page the customer outlet on the picker will be loaded and the what the user saved on will be the item.

How can I achieve this?

Here are my codes:

Here is how I load all of outlet:

var db = DependencyService.Get<ISQLiteDB>();
var conn = db.GetConnection();

var getCode = conn.QueryAsync<ContactsTable>("SELECT * FROM tblContacts LEFT OUTER JOIN tblCustomerMember ON tblCustomerMember.CustomerID = tblContacts.ContactID WHERE CustomerID = ? AND tblCustomerMember.Deleted !='1'", lblCustomer.Text);
var resultCount = getCode.Result.Count;
if (resultCount > 0)
{
   var result = getCode.Result;
   pckOutlet.ItemsSource = result;
}
else
{
    pckOutlet.IsEnabled = false;
}

And here is my XAML:

<Picker x:Name="pckOutlet" Focused="PckOutlet_Focused" SelectedIndexChanged="PckOutlet_SelectedIndexChanged" ItemDisplayBinding="{Binding DisplayText}" StyleClass="formcontrol" IsEnabled="False">
     <Picker.FontFamily>
          <OnPlatform x:TypeArguments="x:String">
               <On Platform="Android" Value="SFProDisplay-Regular.ttf#SFProDisplay-Regular"/>
              </OnPlatform>
      </Picker.FontFamily>
</Picker>

Answer 1

You need to set the SelectedItem property to the previously selected item.

if (resultCount > 0)
{
   var result = getCode.Result;
   pckOutlet.ItemsSource = result;
   pckOutlet.SelectedItem = result.First(outlet => outlet.Id == *PREVIOUSLY_SELECTED_ID*)
}

You may need to store the previously selected ID somewhere where it can survive app resets. Xamarin.Essentials.SecureStorage or Xamarin.Essentials.Preferences can be used for this and is fairly straight forward to use.