C# wpf mvvm如何使用icommand验证数据?
我是WPF开发的新手,我对谷歌也没有进一步的了解。我不明白如何使用C# wpf mvvm如何使用icommand验证数据?,c#,wpf,mvvm,icommand,C#,Wpf,Mvvm,Icommand,我是WPF开发的新手,我对谷歌也没有进一步的了解。我不明白如何使用ICommand验证模型数据。我知道有注释,并且ICommand接口提供了canExecute方法。例如,我想说姓名和姓氏是必需的。 我在我的模型类中用[Required(ErrorMessage=“Title is Required.”]进行了尝试,但没有成功。也许有人能帮我 到目前为止,我有以下几点: public class Student : INotifyPropertyChanged { private str
ICommand
验证模型数据。我知道有注释,并且ICommand
接口提供了canExecute
方法。例如,我想说姓名和姓氏是必需的。
我在我的模型类中用[Required(ErrorMessage=“Title is Required.”]
进行了尝试,但没有成功。也许有人能帮我
到目前为止,我有以下几点:
public class Student : INotifyPropertyChanged
{
private string name;
private string surname;
private int age;
private string course;
public string Course
{
get { return course; }
set
{
course = value;
OnPropertyChanged();
}
}
public int Age
{
get { return age; }
set
{
age = value;
OnPropertyChanged();
}
}
public string Surname
{
get { return surname; }
set
{
surname = value;
OnPropertyChanged();
}
}
public string Name
{
get { return name; }
set
{
name = value;
OnPropertyChanged();
}
}
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged([CallerMemberName] string name = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
}
}
public class StudentViewModel
{
private IList<Student> _studentList;
public StudentViewModel()
{
_studentList = new List<Student>
{
new Student{Name="Todd",Surname="Johnsen",Age=29,Course="Software-Development"},
new Student{Name="Mike",Surname="Kroshka",Age=31,Course="Marketing"},
new Student{Name="Marie",Surname="Tedd",Age=21,Course="Marketing"},
new Student{Name="Susane",Surname="Müller",Age=31,Course="Marketing"},
new Student{Name="Herbert",Surname="Rehl",Age=18,Course="Software-Development"},
new Student{Name="Markus",Surname="Stanz",Age=23,Course="Software-Development"},
new Student{Name="Sabine",Surname="Bergsen",Age=19,Course="Marketing"}
};
}
public IList<Student> Students
{
get { return _studentList; }
set { _studentList = value; }
}
private ICommand mUpdater;
public ICommand UpdateCommand
{
get
{
if(mUpdater == null)
{
mUpdater = new Updater();
}
return mUpdater;
}
set
{
mUpdater = value;
}
}
}
public class Updater : ICommand
{
public bool CanExecute(object parameter)
{
return true;
}
public event EventHandler CanExecuteChanged;
public void Execute(object parameter)
{
}
}
<Window x:Class="Student_list_mvvm_wpf_core.MainWindowView"
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"
xmlns:local="clr-namespace:Student_list_mvvm_wpf_core"
mc:Ignorable="d"
Title="Student-list" Height="350" Width="600">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="auto"></ColumnDefinition>
<ColumnDefinition Width="*"></ColumnDefinition>
<ColumnDefinition Width="*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="auto"></RowDefinition>
<RowDefinition Height="auto"></RowDefinition>
<RowDefinition Height="auto"></RowDefinition>
<RowDefinition Height="auto"></RowDefinition>
<RowDefinition Height="*"></RowDefinition>
</Grid.RowDefinitions>
<Label Grid.Row="0">Name</Label>
<Label Grid.Row="1">Surname</Label>
<Label Grid.Row="2">Age</Label>
<Label Grid.Row="3">Course</Label>
<Button x:Name="btnUpdateStudent" Grid.Row="3" Grid.Column="2"
Width="100" Margin="2" HorizontalAlignment="Left"
Command="{Binding Path=UpdateCommand}">Update Student</Button>
<ListView x:Name="studentGrid" ItemsSource="{Binding Students}"
Grid.Row="4" Grid.ColumnSpan="3" Margin="5">
<ListView.View>
<GridView x:Name="gridStudent">
<GridViewColumn Header="Name" DisplayMemberBinding="{Binding Name}" Width="100" />
<GridViewColumn Header="Surname" DisplayMemberBinding="{Binding Surname}" Width="100" />
<GridViewColumn Header="Age" DisplayMemberBinding="{Binding Age}" Width="50" />
<GridViewColumn Header="Course" DisplayMemberBinding="{Binding Course}" Width="200" />
</GridView>
</ListView.View>
</ListView>
<TextBox Grid.Row="0" Grid.Column="1" Width="200"
HorizontalAlignment="Left" Margin="2"
Text="{Binding SelectedItem.Name, ElementName=studentGrid}"
x:Name="txtName"></TextBox>
<TextBox Grid.Row="1" Grid.Column="1" Width="200"
HorizontalAlignment="Left" Margin="2"
Text="{Binding SelectedItem.Surname, ElementName=studentGrid}"
x:Name="txtSurname"></TextBox>
<TextBox Grid.Row="2" Grid.Column="1" Width="200"
HorizontalAlignment="Left" Margin="2"
Text="{Binding SelectedItem.Age, ElementName=studentGrid}"
x:Name="txtAge"></TextBox>
<TextBox Grid.Row="3" Grid.Column="1" Width="200"
HorizontalAlignment="Left" Margin="2"
Text="{Binding SelectedItem.Course, ElementName=studentGrid}"
x:Name="txtCourse"></TextBox>
</Grid>
公共类学生:INotifyPropertyChanged
{
私有字符串名称;
私家姓;
私人互联网;
私人弦乐课程;
公共弦乐课程
{
获取{返回路线;}
设置
{
课程=价值;
OnPropertyChanged();
}
}
公共信息
{
获取{返回年龄;}
设置
{
年龄=价值;
OnPropertyChanged();
}
}
公共字符串姓氏
{
获取{返回姓氏;}
设置
{
姓氏=价值;
OnPropertyChanged();
}
}
公共字符串名
{
获取{返回名称;}
设置
{
名称=值;
OnPropertyChanged();
}
}
公共事件属性更改事件处理程序属性更改;
public void OnPropertyChanged([CallerMemberName]字符串名称=null)
{
PropertyChanged?.Invoke(这是新的PropertyChangedEventArgs(名称));
}
}
公共课堂学生视图模型
{
私立IList_学生名单;
公共学生视图模型()
{
_studentList=新列表
{
新学生{Name=“Todd”,姓氏=“Johnsen”,年龄=29岁,课程=“软件开发”},
新学生{Name=“Mike”,姓氏=“Kroshka”,年龄=31岁,课程=“营销”},
新学生{Name=“Marie”,姓氏=“Tedd”,年龄=21岁,课程=“营销”},
新生{Name=“Susane”,姓氏=“Müller”,年龄=31岁,课程=“营销”},
新学生{Name=“Herbert”,姓氏=“Rehl”,年龄=18岁,课程=“软件开发”},
新学生{Name=“Markus”,姓氏=“Stanz”,年龄=23岁,课程=“软件开发”},
新生{Name=“Sabine”,姓氏=“Bergsen”,年龄=19岁,课程=“营销”}
};
}
公立学校学生
{
获取{return\u studentList;}
设置{u studentList=value;}
}
私人ICommand mUpdater;
公共ICommand更新命令
{
得到
{
if(mUpdater==null)
{
mUpdater=新的更新程序();
}
返回mUpdater;
}
设置
{
mUpdater=值;
}
}
}
公共类更新程序:ICommand
{
公共布尔CanExecute(对象参数)
{
返回true;
}
公共事件处理程序CanExecuteChanged;
public void Execute(对象参数)
{
}
}
名称
姓
年龄
课程
更新学生
使用验证模型看起来更适合您的情况首先,更新您的视图模型
,使其具有绑定到列表视图
的SelectedItem
:
public Student SelectedStudent
{
get { return _selectedStudent; }
set { _selectedStudent = value; }
}
第二次,更新学生的模型以进行数据验证:
public class Student : INotifyPropertyChanged, IDataErrorInfo
{
private string name;
private string surname;
private int age;
private string course;
public string Course
{
get { return course; }
set
{
course = value;
OnPropertyChanged();
}
}
public int Age
{
get { return age; }
set
{
age = value;
OnPropertyChanged();
}
}
public string Surname
{
get { return surname; }
set
{
surname = value;
OnPropertyChanged();
}
}
public string Name
{
get { return name; }
set
{
name = value;
OnPropertyChanged();
}
}
public string Error => string.Empty;
public string this[string columnName]
{
get
{
string result = null;
if (columnName == "Name")
{
if (string.IsNullOrEmpty(Name))
result = "Name is required.";
}
if (columnName == "Surname")
{
if (string.IsNullOrEmpty(Surname))
result = "Surname is required.";
}
return result;
}
}
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged([CallerMemberName] string name = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
}
}
最后,更新您的xaml:
-在列表视图的
SelectedItem
和您创建的属性之间绑定。
-验证文本框的文本
<TextBox Grid.Row="0" Grid.Column="1" Width="200"
HorizontalAlignment="Left" Margin="2"
Text="{Binding SelectedStudent.Name,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=true, NotifyOnValidationError=False}"
x:Name="txtName"></TextBox>
<TextBox Grid.Row="1" Grid.Column="1" Width="200"
HorizontalAlignment="Left" Margin="2"
Text="{Binding SelectedStudent.Surname,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=true, NotifyOnValidationError=False}"
x:Name="txtSurname"></TextBox>
输出:
这里是一个完整的源代码。如果您坚持使用canExecute
,应该会有所帮助。谢谢您的努力@不客气,如果答案有用,请接受:)
<Button x:Name="btnUpdateStudent" Grid.Row="3" Grid.Column="2"
Width="100" Margin="2" HorizontalAlignment="Left"
Content="Update Student" Command="{Binding UpdateCommand}">
<Button.Style>
<Style TargetType="{x:Type Button}">
<Setter Property="IsEnabled" Value="False" />
<Style.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding ElementName=txtName, Path=(Validation.HasError)}" Value="false" />
<Condition Binding="{Binding ElementName=txtSurname, Path=(Validation.HasError)}" Value="false" />
</MultiDataTrigger.Conditions>
<Setter Property="IsEnabled" Value="True" />
</MultiDataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>