I'm developping a Windows 8 Store Application (c#).
I have a Combobox (cboTeam1) that gets the items from a repository.
private static List<TeamItem> JPLItems = new List<TeamItem>();
public static List<TeamItem> getJPLItems()
{
if (JPLItems.Count == 0)
{
JPLItems.Add(new TeamItem() { Id = 1, Description = "Anderlecht", Image = "Jpl/Anderlecht.png", ItemType = ItemType.JPL });
JPLItems.Add(new TeamItem() { Id = 1, Description = "Beerschot", Image = "Jpl/Beerschot.png", ItemType = ItemType.JPL });
JPLItems.Add(new TeamItem() { Id = 1, Description = "Cercle Brugge", Image = "Jpl/Cercle.png", ItemType = ItemType.JPL });
JPLItems.Add(new TeamItem() { Id = 1, Description = "Charleroi", Image = "Jpl/Charleroi.png", ItemType = ItemType.JPL });
}
return JPLItems;
}
I load the items in the cboTeam1's ItemsSource:
cboTeam1.ItemsSource = ItemRepository.getJPLItems();
When cboTeam1 selectionchanged I do this:
private void cboTeam1_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
Ploeg1.Text = cboTeam1.SelectedValue.ToString();
}
This results in: SportsBetting.Model.TeamItem
Can anyone help me to get the combobox selectedvalue in my textblock (Ploeg1.Text)??
You've nearly answered this for yourself.
private void cboTeam1_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
// cast the selected item to the correct type.
var selected = cboTeam.SelectedValue as TeamItem;
//then access the appropriate property on the object, in this case "Description"
// note that checking for null would be a good idea, too.
Ploeg1.Text = selected.Description;
}
The other option would be to override ToString() in your TeamItem class to return Description. In that case your original code should work fine.
public override string ToString()
{
return this._description; // assumes you have a backing store of this name
}
Related
I am writing a SharePoint app. There I have page with drop down list. I have
a handler for SelectedIndexChanged. I want to get the selected value but as CustomObject and the only option I see is string. I tried SelectedValue and it is still string.
That's how I set the list:
protected void Page_Load(object sender, EventArgs e)
{
List<CustomObject> customList = //retrieving data
myDropDownList.DataSource = customList.Select(x => new { x.Name, Value = x});
myDropDownList.DataTextField = "Name";
myDropDownList.DataValueField = "Value";
myDropDownList.DataBind();
}
And that's one of the ways I tried:
protected void myDropDownList_SelectedIndexChanged(object sender, EventArgs e)
{
var index = groupingDropDownList.SelectedIndex;
CustomObject obj = (CustomObject)myDropDownList.Items[index].Value;
obj.DoSomething();
}
Is it even possible? Or do I have to have somewhere Dictionary with with objects?
You will want to leverage the html5 data attributes that you can then place onto the dropdown options. Here is an example of what you could do with your data.
// add Agencies' addresses as HTML5 data-attributes.
var agencies = agencyNames.ToList();
for (int i = 0; i < requesting_agency.Items.Count - 1; i++) {
requesting_agency.Items[i + 1].Attributes.Add("data-address",
agencies[i].address);
servicing_agency.Items[i + 1].Attributes.Add("data-address",
agencies[i].address);
}
Then when processing the information you could do something like so.
var index = groupingDropDownList.SelectedIndex;
var selectedText = myDropDownList.Items[index].SelectedValue;
var selectedValue = myDropDownList.Items[index].Attributes["attribute"];
// put into obj
// do something with object
Let me know if you have any questions.
You 're binding a object (x => new { x.Name, Value = x}) to dropdown value, you should bind actual value to it.
Test demo:
public class CustomObject
{
public int ID { get; set; }
public string Name { get; set; }
public CustomObject(int _ID,string _Name)
{
this.ID = _ID;
this.Name = _Name;
}
}
public partial class WebForm1 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
List<CustomObject> customList = new List<CustomObject>();
customList.Add(new CustomObject(1,"test1"));
customList.Add(new CustomObject(2,"test2"));
myDropDownList.DataSource = customList.Select(x => new { x.Name, Value = x.ID });
myDropDownList.DataTextField = "Name";
myDropDownList.DataValueField = "Value";
myDropDownList.DataBind();
}
}
When I click a TextCell in a ListView, the row is highlighted.
However, when I programatically select a row / a TextCell, the row isn't highlighted.
Therefore it isn't possible to indicate to the user which value in a ListView is currently selected unless he changes the selection by tapping a row.
Is that a bug or a missing feature, or how could I achieve the highlighting via code?
Sample code is attached below.
using MyApp.Model;
using System.Collections.Generic;
using Xamarin.Forms;
namespace MyApp
{
public class IntSelector : ContentPage
{
private ListView m_ListView;
public IntSelector(int uSelectedInt)
{
DataTemplate nTemplate = new DataTemplate(typeof(TextCell));
// We can set data bindings to our supplied objects.
nTemplate.SetBinding(TextCell.TextProperty, "String");
nTemplate.SetBinding(TextCell.DetailProperty, "Int");
List<clsStringInt> nList = new List<clsStringInt>();
clsStringInt nItem1 = new clsStringInt { String = "German", Int = 1031 };
clsStringInt nItem2 = new clsStringInt { String = "English", Int = 1033 };
clsStringInt nItem3 = new clsStringInt { String = "Spanish", Int = 1034 };
nList.Add(nItem1);
nList.Add(nItem2);
nList.Add(nItem3);
m_ListView = new ListView();
m_ListView.ItemTemplate = nTemplate;
m_ListView.ItemsSource = nList;
m_ListView.ItemSelected += this.OnSelection;
m_ListView.SelectedItem = nItem2;//this triggers the "OnSelection" event, so it works
nItem2.String = "->> " + nItem2.String; //the item's new string is display in the ListView, so that works as well
//what DOESN'T work is the highliting
this.Content = m_ListView;
}
void OnSelection(object sender, SelectedItemChangedEventArgs e)
{
if (e.SelectedItem == null)
{
return; //ItemSelected is called on deselection, which results in SelectedItem being set to null
}
clsStringInt n = (clsStringInt)e.SelectedItem;
string sSelectedIntAsString = n.Int.ToString();
DisplayAlert("Item Selected", sSelectedIntAsString, "Ok");
}
}
}
namespace MyApp.Model
{
public class clsStringInt
{
public string String { get; set; }
public int Int { get; set; }
}
}
As mentioned in the comments you are testing on a UWP Forms app which this appears to be a bug specifically on that platform seeing how it works fine on Android and iOS.
I was able to work around this by setting the selected item in OnAppearing instead of in the Page constructor to get it to highlight.
What I would like to do is to populate a drop down menu from a database.
First of all I plan to use a combo box.
I have created an object that contains the data that I need to take from the database. The object is as follows
namespace RLMD
{
public class FlashCardLevel
{
private int intFCLId;
private String strFCLName;
public FlashCardLevel(int intFCLId, String strFCLName)
{
this.intFCLId = intFCLId;
this.strFCLName = strFCLName;
}
public int IntFCLId
{
get { return intFCLId; }
set { this.intFCLId = value; }
}
public String StrFCLName
{
get { return strFCLName; }
set { this.strFCLName = value; }
}
}
}
What I need to do is to add a list of items from a database, but for ease of use I have simulated given some sample data.
public List<FlashCardLevel> Rifle(List<FlashCardLevel> fcLevel)
{
fcLevel.Add(new FlashCardLevel(1, "Severe"));
fcLevel.Add(new FlashCardLevel(2, "Moderate"));
fcLevel.Add(new FlashCardLevel(3, "Mild"));
fcLevel.Add(new FlashCardLevel(4, "Slight"));
return fcLevel;
}
I'm calling the method here.
List<FlashCardLevel> fcLevel = new List<FlashCardLevel>();
talkToDatabase.Rifle(fcLevel);
this.comboCardLevel.DataSource = fcLevel;
this.comboCardLevel.DisplayMember = "Name";
this.comboCardLevel.ValueMember = "Value";
The combobox is displaying no information.
I would appreciate any help
Updated:
The DisplayMember Property should be referring to FlashCardLevel (class), Property StrFCLName and ValueMember should be pointing to IntFCLId.
List<FlashCardLevel> fcLevel = new List<FlashCardLevel>();
talkToDatabase.Rifle(fcLevel);
this.comboCardLevel.DataSource = listFromDatabase;
this.comboCardLevel.DisplayMember = "StrFCLName";
this.comboCardLevel.ValueMember = "IntFCLId";
The DisplayMember and ValueMember should point to your properties name.
this.comboCardLevel.DisplayMember = "IntFCLId";
this.comboCardLevel.ValueMember = "StrFCLName";
I have a ParameterItem class for adding some items to a listbox:
class ParameterItem
{
public string Name { get; set; }
public string Value { get; set; }
public ParameterItem(string name, string value)
{
Name = name;
Value = value;
}
public override string ToString()
{
return Name + " = " + Value;
}
public override bool Equals(object obj)
{
if (obj is ParameterItem)
return (Name == ((ParameterItem)obj).Name);
return false;
}
public override int GetHashCode()
{
return Name.ToLowerInvariant().GetHashCode();
}
}
And you can add items to the listbox using two textboxes (name and value). When you click on an item in the listbox, the textboxes get filled with the name and the value of the ParameterItem. I have the following code to change the contents of the selected ParameterItem in the listbox:
private void btnSaveParameter_Click(object sender, EventArgs e)
{
ParameterItem currentParameter = new ParameterItem(textParameterName.Text,
textParameterValue.Text);
// If we already have the parameter set then edit it.
if (lstbxSetParameters.Items.Contains(currentParameter))
{
((ParameterItem)lstbxSetParameters.SelectedItem).Value = currentParameter.Value;
lstbxSetParameters.;
}
// If it's not set yet then add it to the listbox.
else
{
lstbxSetParameters.Items.Add(currentParameter);
textParameterName.Text = String.Empty;
textParameterValue.Text = String.Empty;
}
}
The problem is, even though I can change the contents of the selected ParameterItem, in the listbox, it still looks like it is not changed.
For example I have a parameter in the list box:
TestParameter = 10
And I change the ParameterItem to
TestParameter = 5
but in the listbox it still looks like
TestParameter = 10
even though it's been changed.
How can I solve this problem? I think the listbox item should call the ToString() method of the ParameterItem again and refresh itself but how?
Or is there a better way to add key value pairs in the listbox?
You can change the selected item by remove it and insert it again.
// If we already have the parameter set then edit it.
if (lstbxSetParameters.Items.Contains(currentParameter))
{
var newItem = new ParameterItem((lstbxSetParameters.SelectedItem as ParameterItem).Name, currentParameter.Value);
var index = lstbxSetParameters.SelectedIndex;
lstbxSetParameters.Items.RemoveAt(index);
lstbxSetParameters.Items.Insert(index, newItem);
lstbxSetParameters.SelectedIndex = index;
}
My solution:
string[] nList = new string[lb.Items.Count];
nList = lb.Items.OfType<string>().ToArray();
nList[lb.SelectedIndex] = newValue;
lb.Items.Clear();
lb.Items.AddRange(nList);
This way instead of changing the selected item (with a lot of problem) I reloaded the Listbox with the item changed in the array.
I want a ListBox full of items. Although, each item should have a different value.
So when the user selects an item and presses a button, a method will be called which will use the value the select item has.
I don't want to reveal the item values to the user.
EDIT: This is not for ASP.NET, it's for a Windows Forms application. I just thought the HTML example would be easy to read.
I have the inspiration from HTML:
<form>
<input type="radio" name="sex" value="Value1" /> Male
<br />
<input type="radio" name="sex" value="Value2" /> Female
</form>
This also allows me to use different values than what the user sees.
You can choose what do display using the DisplayMember of the ListBox.
List<SomeData> data = new List<SomeData>();
data.Add(new SomeData() { Value = 1, Text= "Some Text"});
data.Add(new SomeData() { Value = 2, Text = "Some Other Text"});
listBox1.DisplayMember = "Text";
listBox1.DataSource = data;
When the user selects an item, you can read the value (or any other property) from the selected object:
int value = (listBox1.SelectedItem as SomeData).Value;
Update: note that DisplayMember works only with properties, not with fields, so you need to alter your class a bit:
public class SomeData
{
public string Value { get; set; };
public string Text { get; set; };
}
items have a property called 'Tag', which you can use to store any information you want (hidden from the user)
ListViewItem myItem = new ListViewItem();
myItem.Text = "Users see this";
myItem.Tag = "Users don't see this";
(or set the appropriate properties in the property explorer)
Very simple:
foreach(var item in *Your Source List*)
{
ListItem dataItem = new ListItem();
dataItem.Text = "value to show";
dataItem.Value = *another value you want*;
listBox.Items.Add(dataItem);
}
As stated by the 1st answer, the use of DisplayMember works whether you are using asp.net or winforms.
And to comment a bit more, it also works if you are using the rather old fashion Items.add way of adding items to a ListBox.
Just for fun, here is a simple demo of what you need (just create a new form and drop on it a ListBox and a Label):
public partial class Form1 : Form
{
class Customer
{
public string FirstName { get; set; }
public string LastName { get; set; }
public override string ToString()
{
return string.Format("{0} {1}", LastName, FirstName);
}
}
public Form1() { InitializeComponent(); }
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
listBox1.DisplayMember = "LastName";
listBox1.DataSource = GetCustomers();
//listBox1.Items.AddRange(GetCustomers().ToArray());
}
private IEnumerable<Customer> GetCustomers()
{
return new List<Customer>()
{
new Customer() { FirstName = "Gustav", LastName = "MAHLER" },
new Customer() { FirstName = "Johann Sebastian", LastName = "BACH" }
};
}
private void lb_SelectedIndexChanged(object sender, EventArgs e)
{
label1.Text = listBox1.SelectedItem.ToString();
}
}
Enjoy
PS: #2nd post Tag is not available to ListBox: because it accepts an array of object, not a specific item container like ListView... but you don't need any in your case. Tag is useful when you want to carry additional data along with a specific TreeViewItem or ListViewItem for example.
By the way, Tag is defined at the Control level and so exists for Button, Label, and so on... but for my part I think it is rather a bad idea to store business data in it (untyped, UI coupled...) apart from the ListView and TreeView cases for which it is rather convenient.
Easy!
protected void Page_Load(object sender, EventArgs e)
{
llenaListBox(ListBox1, 0, 10);
}
private void llenaListBox(ListBox PoListBox, int PiMinimo, int PiMaximo)
{
int Li;
for (Li = PiMinimo; Li <= PiMaximo; Li++)
{
ListItem obj = new ListItem();
obj.Text = Li.ToString();
obj.Value = Li.ToString();
PoListBox.Items.Add(obj);
}
}