WPF Combobox绑定Dictionary/ObservableDictionary
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2022-06-07 18:36:54
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WPF Combobox绑定Dictionary / ObservableDictionary
一、WPFcombobox绑定dictionary
ViewModel中存在以下字典数据,要将其绑定到xaml的Combox中
private Dictionary<long,string> _MusicList=
new Dictionary<long, string> {
{ 3778678, "云音乐热歌榜" },
{ 2248307886, "抖音热歌" },
{ 3779629, "云音乐新歌榜" },
{ 4395559, "华语金曲榜" },
{ 64016, "中国TOP排行榜(内地榜)" },
{ 112504, "中国TOP排行榜(港台榜)" },
{ 19723756, "云音乐飙升榜" },
{ 2884035, "网易原创歌曲榜" },
};
public Dictionary<long,string> MusicList
{
get { return this._MusicList; }
set
{
this._MusicList = value;
RaisePropertyChanged(() => MusicList);
}
}
字典的绑定
<ComboBox Grid.Row="1" ItemsSource="{Binding MusicList}"
DisplayMemberPath="Value"
SelectedValuePath = "Key"></ComboBox>
二、ObservableDictionary
public class ObservableDictionary<TKey, TValue> : Dictionary<TKey, TValue>, INotifyCollectionChanged, INotifyPropertyChanged
{
public ObservableDictionary()
: base()
{ }
private int _index;
public event NotifyCollectionChangedEventHandler CollectionChanged;
public event PropertyChangedEventHandler PropertyChanged;
public new KeyCollection Keys
{
get { return base.Keys; }
}
public new ValueCollection Values
{
get { return base.Values; }
}
public new int Count
{
get { return base.Count; }
}
public new TValue this[TKey key]
{
get { return this.GetValue(key); }
set { this.SetValue(key, value); }
}
public TValue this[int index]
{
get { return this.GetIndexValue(index); }
set { this.SetIndexValue(index, value); }
}
public new void Add(TKey key, TValue value)
{
base.Add(key, value);
this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, this.FindPair(key), _index));
OnPropertyChanged("Keys");
OnPropertyChanged("Values");
OnPropertyChanged("Count");
}
public new void Clear()
{
base.Clear();
this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
OnPropertyChanged("Keys");
OnPropertyChanged("Values");
OnPropertyChanged("Count");
}
public new bool Remove(TKey key)
{
var pair = this.FindPair(key);
if (base.Remove(key))
{
this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, pair, _index));
OnPropertyChanged("Keys");
OnPropertyChanged("Values");
OnPropertyChanged("Count");
return true;
}
return false;
}
protected void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
{
if (this.CollectionChanged != null)
{
this.CollectionChanged(this, e);
}
}
protected void OnPropertyChanged(string propertyName)
{
if (this.PropertyChanged != null)
{
this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
#region private方法
private TValue GetIndexValue(int index)
{
for (int i = 0; i < this.Count; i++)
{
if (i == index)
{
var pair = this.ElementAt(i);
return pair.Value;
}
}
return default(TValue);
}
private void SetIndexValue(int index, TValue value)
{
try
{
var pair = this.ElementAtOrDefault(index);
SetValue(pair.Key, value);
}
catch (Exception)
{
}
}
private TValue GetValue(TKey key)
{
if (base.ContainsKey(key))
{
return base[key];
}
else
{
return default(TValue);
}
}
private void SetValue(TKey key, TValue value)
{
if (base.ContainsKey(key))
{
var pair = this.FindPair(key);
int index = _index;
base[key] = value;
var newpair = this.FindPair(key);
this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Replace, newpair, pair, index));
OnPropertyChanged("Values");
OnPropertyChanged("Item[]");
}
else
{
this.Add(key, value);
}
}
private KeyValuePair<TKey, TValue> FindPair(TKey key)
{
_index = 0;
foreach (var item in this)
{
if (item.Key.Equals(key))
{
return item;
}
_index++;
}
return default(KeyValuePair<TKey, TValue>);
}
private int IndexOf(TKey key)
{
int index = 0;
foreach (var item in this)
{
if (item.Key.Equals(key))
{
return index;
}
index++;
}
return -1;
}
#endregion
}
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