Answers

• PatrickKealy AUMember ✭

  July 2014

  Did u have any luck? Mine is the same problem! please share if u got the multi select list working...

  0
• d_dblu CAUniversity ✭✭

  July 2014

  I had to put this aside because I ran out of time but extending the ListView wasn't possible due to the inability to override the single selection behavior it encapsulates. If the accessors change in a future version then it might be possible but otherwise I think mapping a CustomRenderer to a UITableView that is setup for multi-select would be the approach.

  Anyone else get this going?

  0
• RyanHatfieldOld USMember, Insider ✭✭✭

  July 2014

  does it have to be a cell?
  You could render a list of buttons, \

  List<Button> buttonList
  

  And set the button command to toggle the colors of the button. when you're done, use some linq on the buttonList and you can figure out what's selected. Something like:

  buttonList.where(b => b.Selected).ToList()
  

  This can all be done in top level Xamarin.Forms without custom renders. If you're interested I could probably whip up an example of what I mean. I've done it in a recent project (Podio integration) but it's waaaaay too involved to dig out. I'd rather make something clean from scratch.

  0
• d_dblu CAUniversity ✭✭

  July 2014 edited July 2014

  That sounds way easier, but I thought that you have to use cells with the list. Also are there any performance issues? If it isn't a cell how is the queue/dequeue reusable cell mechanism working? I'd be interested to see the example. If it works fine I'd be pretty happy with this.

  0
• RyanHatfieldOld USMember, Insider ✭✭✭

  July 2014 edited July 2014 Accepted Answer

  Here's 2 videos about creating a toggle button. This should get you half way there with creating a decent looking multi select list.

  Part1
  Part2

  the ToggleButton class

  public class ToggleButton : Button
  {
      #region BindableProps
      public static readonly BindableProperty SelectedProperty = BindableProperty.Create<ToggleButton, bool>(p => p.Selected, default(bool));
  
      public bool Selected
      {
          get { return (bool)GetValue(SelectedProperty); }
          set { SetValue(SelectedProperty, value); }
      }
  
      public static readonly BindableProperty SelectedTextColorProperty = BindableProperty.Create<ToggleButton, Color>(p => p.SelectedTextColor, default(Color));
  
      public Color SelectedTextColor
      {
          get { return (Color)GetValue(SelectedTextColorProperty); }
          set { SetValue(SelectedTextColorProperty, value); }
      }
  
      public static readonly BindableProperty SelectedBackgroundColorProperty = BindableProperty.Create<ToggleButton, Color>(p => p.SelectedBackgroundColor, default(Color));
  
      public Color SelectedBackgroundColor
      {
          get { return (Color)GetValue(SelectedBackgroundColorProperty); }
          set { SetValue(SelectedBackgroundColorProperty, value); }
      }
  
      public static readonly BindableProperty DeSelectedTextColorProperty = BindableProperty.Create<ToggleButton, Color>(p => p.DeSelectedTextColor, default(Color));
  
      public Color DeSelectedTextColor
      {
          get { return (Color)GetValue(DeSelectedTextColorProperty); }
          set { SetValue(DeSelectedTextColorProperty, value); }
      }
  
      public static readonly BindableProperty DeSelectedBackgroundColorProperty = BindableProperty.Create<ToggleButton, Color>(p => p.DeSelectedBackgroundColor, default(Color));
  
      public Color DeSelectedBackgroundColor
      {
          get { return (Color)GetValue(DeSelectedBackgroundColorProperty); }
          set { SetValue(DeSelectedBackgroundColorProperty, value); }
      }
      #endregion
  
      private void setColors()
      {
          if (this.Selected)
          {
              this.TextColor = SelectedTextColor;
              this.BackgroundColor = SelectedBackgroundColor;
          }
          else
          {
              this.TextColor = DeSelectedTextColor;
              this.BackgroundColor = DeSelectedBackgroundColor;
          }
      }
      public ToggleButton()
      {
          this.Clicked += (sender, e) =>
          {
              this.Selected = !this.Selected;
          };
          this.BorderRadius = 0;
          this.BorderWidth = 0;
      }
  
      protected override void OnPropertyChanged(string propertyName = null)
      {
          base.OnPropertyChanged(propertyName);
          List<string> propNames = new List<string> 
          {
              ToggleButton.SelectedProperty.PropertyName,
              ToggleButton.SelectedBackgroundColorProperty.PropertyName,
              ToggleButton.DeSelectedBackgroundColorProperty.PropertyName, 
              ToggleButton.SelectedTextColorProperty.PropertyName,
              ToggleButton.DeSelectedTextColorProperty.PropertyName
          };
          if (propertyName != null && propNames.Contains(propertyName))
          {
              setColors();
          }
      }
  }
  

  the page definition

  public static Page GetMainPage()
  {
      ContentPage page = new ContentPage();
      StackLayout layout = new StackLayout();
      Label countLabel = new Label { Text = "Count: 0" };
      ScrollView scrollLayout = new ScrollView();
      StackLayout buttonLayout = new StackLayout();
      List<ToggleButton> buttons = new List<ToggleButton>();
  
      for (int i = 0; i < 50; i++)
      {
          ToggleButton button = new ToggleButton
          {
              Selected = false,
              Text = "Button " + i,
              DeSelectedBackgroundColor = Color.White,
              DeSelectedTextColor = Color.Black,
              SelectedBackgroundColor = Color.Black,
              SelectedTextColor = Color.White,
          };
          button.Clicked += (sender, e) =>
          {
              countLabel.Text = "Count: " + buttons.Where(b => b.Selected == true).Count().ToString();
          };
          buttonLayout.Children.Add(button);
          buttons.Add(button);
      }
  
      page.Content = layout;
      layout.Children.Add(countLabel);
      layout.Children.Add(scrollLayout);
      scrollLayout.Content = buttonLayout;
      return page;
  }
  

  Not sure I answered the original question... hopefully some of this would be useful.

  I didn't realize how loud my keyboard was! ha. I need a microphone and some decent screen casting software.

  5
• RyanHatfieldOld USMember, Insider ✭✭✭

  July 2014 Accepted Answer

  Also a bit random, but here's my bindable property snippet

  <?xml version="1.0" encoding="utf-8"?>
  <CodeSnippets xmlns="http://schemas.microsoft.com/VisualStudio/2005/CodeSnippet">
    <CodeSnippet Format="1.0.0">
      <Header>
        <SnippetTypes>
          <SnippetType>Expansion</SnippetType>
        </SnippetTypes>
        <Title>bprop</Title>
        <Author>Microsoft Corporation</Author>
        <Description>Code snippet for an automatically implemented $name$Property
  Language Version: C# 3.0 or higher</Description>
        <HelpUrl>
        </HelpUrl>
        <Shortcut>bprop</Shortcut>
      </Header>
      <Snippet>
        <Declarations>
          <Literal Editable="true">
            <ID>name</ID>
            <ToolTip>name</ToolTip>
            <Default>name</Default>
            <Function>
            </Function>
          </Literal>
          <Literal Editable="true">
            <ID>owner</ID>
            <ToolTip>owner</ToolTip>
            <Default>Owner</Default>
            <Function>
            </Function>
          </Literal>
          <Literal Editable="true">
            <ID>type</ID>
            <ToolTip>type</ToolTip>
            <Default>Type</Default>
            <Function>
            </Function>
          </Literal>
        </Declarations>
        <Code Language="csharp"><![CDATA[public static readonly BindableProperty $name$Property = BindableProperty.Create<$owner$,$type$>(p => p.$name$, default($type$));
  
  public $type$ $name$
  {
      get { return ($type$)GetValue($name$Property); }
      set { SetValue($name$Property, value); }
  }$end$]]></Code>
      </Snippet>
    </CodeSnippet>
  </CodeSnippets>
  

  5
• PatrickKealy AUMember ✭

  July 2014

  This is simply great and surely helpful for someone like me looking for a quick alternative to implement a multiselect list. Thanks for support and time.

  0
• FredyWenger CHInsider ✭✭✭✭✭

  October 2014 Accepted Answer

  @RyanHatfield, @PatrickKealy‌:
  Hi all
  For your informaton:
  I have posted my solution for a (simple) "multiselect ListView" here:

  forums.xamarin.com/discussion/17885/multiselect-listviews#latest

  5