我想在combobox1选择改变事件后填充我的combobox2。
这是我的XAML的一部分:
<ComboBox Name="cmbWorkcode"
ItemsSource="{Binding Workcodes}"
DisplayMemberPath="WorkcodeName"
SelectedValuePath="WorkcodeID"
SelectedValue="{Binding Path=WorkcodeId, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
<ComboBox Name="cmbProcess"
ItemsSource="{Binding Processes}"
DisplayMemberPath="ProcessName" SelectedValuePath="ProcessId"
SelectedValue="{Binding Path=ProcessId, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
我的ViewModel的一部分:
class MainWindowViewModel : ObservableObject
{
private ObservableCollection<Workcode> _workcodes = new ObservableCollection<Workcode>();
public ObservableCollection<Workcode> Workcodes
{
get { return _workcodes; }
set
{
_workcodes = value;
OnPropertyChanged("Workcodes");
}
}
private int _workcodeId;
public int WorkcodeId
{
get { return _workcodeId; }
set
{
_workcodeId = value;
OnPropertyChanged("WorkcodeId");
}
}
private ObservableCollection<Process> _processes = new ObservableCollection<Process>();
public ObservableCollection<Process> Processes
{
get { return _processes; }
set
{
_processes = value;
OnPropertyChanged("Processes");
}
}
private int _processId;
public int ProcessId
{
get { return _processId; }
set
{
_processId = value;
OnPropertyChanged("ProcessId");
}
}
public MainWindowViewModel()
{
PopulateWorkcode();
}
private void PopulateWorkcode()
{
using (var db = new DBAccess())
{
db.ConnectionString = ConfigurationManager.ConnectionStrings["connString"].ConnectionString;
db.Query = @"SELECT workcodeId, workcode FROM workcode";
DataTable data = db.GetData();
if (data != null)
{
foreach (DataRow row in data.Rows)
{
int workcodeId = Convert.ToInt32(row["workcodeId"].ToString());
string workcodeName = row["workcode"].ToString();
_workcodes.Add(new Workcode(workcodeId, workcodeName));
}
}
}
}
private void PopulateProcess()
{
using (var db = new DBAccess())
{
db.ConnectionString = ConfigurationManager.ConnectionStrings["connString"].ConnectionString;
db.Query = @"SELECT ProcessId, ProcessName FROM `process` WHERE WorkcodeId = @workcodeId";
DataTable data = db.GetData(new[] {new MySqlParameter("@workcodeId", _workcodeId.ToString())});
if (data != null)
{
foreach (DataRow row in data.Rows)
{
int id = Convert.ToInt32(row["ProcessId"].ToString());
string name = row["ProcessName"].ToString();
_processes.Add(new Process(id, name));
}
}
}
}
}
我的问题是我不知道在哪里触发我的PopulateProcess()方法,以便根据combobox1的选择填充我的combobox2。感谢您的所有时间和帮助! :)
- 编辑 -
public class ObservableObject : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string propertyName)
{
var handler = PropertyChanged;
if (handler != null)
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
public class Workcode
{
public int WorkcodeId { get; set; }
public string WorkcodeName { get; set; }
public Workcode(int id, string name)
{
WorkcodeId = id;
WorkcodeName = name;
}
}
答案 0 :(得分:3)
最初第二个组合框是空的,并且选择第一个组合框改变后只是瞳孔化过程
private int _workcodeId;
public int WorkcodeId
{
get { return _workcodeId; }
set
{
_workcodeId = value;
OnPropertyChanged("WorkcodeId");
if(WorkcodeID>0) PopulateProcess();
}
}
答案 1 :(得分:2)
我可以理解你想让下一个组合框根据以前的值填充数据。由于我没有类型的课程,我将举一个简单的例子,
class ItemListViewModel<T> : INotifyPropertyChanged where T : class
{
private T _item;
private ObservableCollection<T> _items;
public ItemListViewModel()
{
_items = new ObservableCollection<T>();
_item = null;
}
public void SetItems(IEnumerable<T> items)
{
Items = new ObservableCollection<T>(items);
SelectedItem = null;
}
public ObservableCollection<T> Items
{
get { return _items; }
private set
{
_items = value;
RaisePropertyChanged("Items");
}
}
public T SelectedItem
{
get { return _item; }
set
{
_item = value;
RaisePropertyChanged("SelectedItem");
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void RaisePropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
然后将主视图模型绑定到视图的DataContext。让Load方法做你想做的事情
class MyViewModel : INotifyPropertyChanged
{
public MyViewModel()
{
First = new ItemListViewModel<string>();
Second = new ItemListViewModel<string>();
Third = new ItemListViewModel<string>();
First.PropertyChanged += (s, e) => Update(e.PropertyName, First, Second, LoadSecond);
Second.PropertyChanged += (s, e) => Update(e.PropertyName, Second, Third, LoadThird);
LoadFirst();
}
public ItemListViewModel<string> First { get; set; }
public ItemListViewModel<string> Second { get; set; }
public ItemListViewModel<string> Third { get; set; }
private void LoadFirst()
{
First.SetItems(new List<string> { "One", "Two", "Three" });
}
private void LoadSecond()
{
Second.SetItems(new List<string> { "First", "Second", "Third" });
}
private void LoadThird()
{
Third.SetItems(new List<string> { "Firsty", "Secondly", "Thirdly" });
}
private void Update<T0, T1>(string propertyName, ItemListViewModel<T0> parent, ItemListViewModel<T1> child, Action loadAction)
where T0 : class
where T1 : class
{
if (propertyName == "SelectedItem")
{
if (parent.SelectedItem == null)
{
child.SetItems(Enumerable.Empty<T1>());
}
else
{
loadAction();
}
}
}
public event PropertyChangedEventHandler PropertyChanged;
}
在XAML中,
<ComboBox ItemsSource="{Binding First.Items}" SelectedItem="{Binding First.SelectedItem}" />
<ComboBox ItemsSource="{Binding Second.Items}" SelectedItem="{Binding Second.SelectedItem}" />
<ComboBox ItemsSource="{Binding Third.Items}" SelectedItem="{Binding Third.SelectedItem}" />
答案 2 :(得分:1)
问题在这里
<ComboBox Name="cmbWorkcode"
ItemsSource="{Binding Workcodes}"
DisplayMemberPath="WorkcodeName"
SelectedValuePath="WorkcodeId"
SelectedValue="{Binding Path=WorkcodeId, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
应该 WorkcodeId 而不是 WorkcodeID 。休息你可以尝试Nishanth回复
public int WorkcodeId
{
get { return _workcodeId; }
set
{
if(_workcodeId !=value)
{
_workcodeId = value;
OnPropertyChanged("WorkcodeId");
PopulateProcess();
}
}
}