【发布时间】：2011-06-29 21:07:27
【问题描述】：
我有 Master/Detail – datagrid/dataform 并在选择项目后显示在数据表单中以进行更新，但我在数据绑定或填充组合框时遇到问题，并将 SelectedEmployee.departmentid 设置为 selectedvalue。
这里有 2 个问题：
1.在 EmployeeViewModel 中，这段代码不起作用，问题是为什么？
private ObservableCollection<department> _departments;
public ObservableCollection<department> Departments
{
get { return _departments; }
set
{
_departments = value;
RaisePropertyChanged("Departments");
}
}
但是这段代码可以正常工作
private ObservableCollection<department> _departments;
public ObservableCollection<department> Departments
{
get {
if (_departments == null)
{
_departments = new ObservableCollection<department> {
new department()
{ id = 1, departmentname = "Technical " + 1, },
new department()
{ id = 2, departmentname = "Technical " + 2, },
new department()
{ id = 3, departmentname = "Technical " + 3, }
};
}
return _departments;
}
set
{
_departments = value;
RaisePropertyChanged("Departments");
}
}
2。 DataForm 内部和外部的 Combobox 的行为是不同的。外面可以，里面不行。我觉得这里需要用到ItemsSource中的Source，但是不知道怎么用。那么还有一个问题是如何解决呢？
employeeView.xaml
<navigation:Page xmlns:local="clr-namespace:departmentTechManager"
x:Class="departmentTechManager.Views.employeeView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
xmlns:navigation="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"
d:DesignWidth="820" d:DesignHeight="780"
Title="employees"
Style="{StaticResource PageStyle}"
xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk"
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
xmlns:mvvmlightcmd="clr-namespace:GalaSoft.MvvmLight.Command;assembly=GalaSoft.MvvmLight.Extras.SL4"
xmlns:data="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data"
xmlns:dataformtoolkit="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data.DataForm.Toolkit"
DataContext="{Binding employeeStatic, Source={StaticResource Locator}}">
<data:DataGrid Grid.Row="0" x:Name="dgEmployees" CanUserSortColumns="true"
IsReadOnly="true" AutoGenerateColumns="true"
ItemsSource="{Binding Employees}"
SelectedItem="{Binding SelectedEmployee, Mode=TwoWay}" Margin="0,36,-123,0"></data:DataGrid>
<dataformtoolkit:DataForm x:Name="dfDetails"
CurrentItem="{Binding SelectedEmployee}" AutoGenerateFields="False"
CommitButtonContent="Save" CommandButtonsVisibility="Edit, Commit, Cancel">
<dataformtoolkit:DataForm.EditTemplate>
<DataTemplate>
<StackPanel>
<dataformtoolkit:DataField Label="name">
<TextBox Text="{Binding name, Mode=TwoWay}" /></dataformtoolkit:DataField>
<dataformtoolkit:DataField Label="departments">
<ComboBox ItemsSource="{Binding Departments}"
DisplayMemberPath="departmentname"
SelectedValuePath="id"
SelectedValue="{Binding Path=SelectedEmployee.departmentid, Mode=TwoWay}" />
</dataformtoolkit:DataField>
</StackPanel>
</DataTemplate>
</dataformtoolkit:DataForm.EditTemplate>
<i:Interaction.Triggers><i:EventTrigger EventName="EditEnded">
<mvvmlightcmd:EventToCommand Command="{Binding SaveEmployeesCommand}"/>
</i:EventTrigger></i:Interaction.Triggers>
</dataformtoolkit:DataForm>
在 ViewModelLocator.cs 中：
public ViewModelLocator()
{
_sp = ServiceProviderBase.Instance;
Createdepartment();
Createemployee();
}
#region EmployeeViewModel
private static EmployeeViewModel _employee;
public static EmployeeViewModel employeeStatic
{
get
{
if (_employee == null)
{
Createemployee();
}
return _employee;
}
}
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance",
"CA1822:MarkMembersAsStatic",
Justification = "This non-static member is needed for data binding purposes.")]
public EmployeeViewModel employee
{
get
{
return employeeStatic;
}
}
public static void Clearemployee()
{
//do it later
//_employee.Cleanup();
_employee = null;
}
public static void Createemployee()
{
if (_employee == null)
{
_employee = new EmployeeViewModel(_sp.PageConductor, _sp.EmployeeDataService);
}
}
#endregion
#region DepartmentViewModel
private static DepartmentViewModel _department;
public static DepartmentViewModel departmentStatic
{
get
{
if (_department == null)
{
Createdepartment();
}
return _department;
}
}
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance",
"CA1822:MarkMembersAsStatic",
Justification = "This non-static member is needed for data binding purposes.")]
public DepartmentViewModel department
{
get
{
return departmentStatic;
}
}
public static void Cleardepartment()
{
//do it later
//_department.Cleanup();
_department = null;
}
public static void Createdepartment()
{
if (_department == null)
{
_department = new DepartmentViewModel(_sp.PageConductor, _sp.DepartmentDataService);
}
}
#endregion
有人可以帮帮我吗？
combox 是空的。但现在我可以用这样的部门填充它：
departmentTechManagerDomainService.metadata.cs
[MetadataTypeAttribute(typeof(employee.employeeMetadata))]
public partial class employee
{
[Include]
public department department { get; set; }
public Nullable<int> departmentid { get; set; }
public string name { get; set; }
}
departmentTechManagerDomainService.cs
public IQueryable<employee> GetEmployees()
{return this.ObjectContext.employees.Include("department").OrderBy(e=>e.name);}
这里是 ViewModel 代码：
private ObservableCollection<department> _departments;
public ObservableCollection<department> Departments
{
get { return _departments; }
set
{
_departments = value;
RaisePropertyChanged("Departments");
}
}
private department _selectedDepartment;
public department SelectedDepartment
{
get { return _selectedDepartment; }
set
{
_selectedDepartment = value;
RaisePropertyChanged("SelectedDepartment");
}
}
private void InitializeModels()
{
Employees = new ObservableCollection<employee>();
SelectedEmployee = new employee();
NewEmployee = new employee();
//new
Departments = new ObservableCollection<department>();
SelectedDepartment = new department();
}
private void GetEmployeesCallback(IEnumerable<employee> employees)
{
if (employees != null)
{
foreach (var employee in employees)
{
Employees.Add(employee);
//new
if (!Departments.Contains(employee.department))
Departments.Add(employee.department);
}
if (Employees.Count > 0)
{
SelectedEmployee = Employees[0];
}
}
}
我区分了部门，但这里只是那些已经被选中的部门，但这里不是那些尚未被选中的部门，而且组合框仍然没有填充 DataForm 中的部门。 ?!
【问题讨论】：
-
关于第一个问题 - 它如何不起作用以及在哪种情况下？
-
我在问题中添加了代码。它在字符串“组合框只是空的。但现在我可以用这样的部门填充它”
标签： silverlight data-binding mvvm combobox dataform