how to get the position of an element in a list in xamarin

Question

how to get the position of an element in a list in xamarin. for example:

List<double> lists = new List<double> { 80 , 90 , 102 , 99 }

if you search for "90" The result is position #2

if you search for "99" The result is position #4

Answer 1

Hello,

You can use List<T>.IndexOf Method to the index. If you want to get the position, you need to add 1. Here is test code.

I add Button click event for testing. If search result is exclude the List, you get -1 when you execute list.IndexOf();. I notice you search text is string, you need to use double.Parse("90") to convert it from string to double.

   public partial class MainPage : ContentPage  
       {  
           List<double> list;  
           public MainPage()  
           {  
               InitializeComponent();  
              list = new List<double>() {80,90, 102,99};  
           }  
          private void Button_Clicked(object sender, EventArgs e)  
           {     
               var res=  list.IndexOf(double.Parse("90"));  
              if (res != -1)  
               {  
                   string ResPostion = "Postion#" + (res + 1);  
                   DisplayAlert("info", ResPostion, "OK");  
               }  
                
           }  
       }  

Best Regards,

Leon Lu

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