我遇到问题通过我的ViewModel在MVVM Silverlight应用程序中绑定自定义用户控件。基本控件是带有三个文本框的日期输入表单。我使用MVVM在三个属性中获取文本框数据,然后将其验证为Date。
将下面的控件绑定到MVVM对我来说很好:
用户控件的XAML: DateControl.xaml
<UserControl x:Class="DatePicker.DateControl"
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">
<Grid x:Name="LayoutRoot" Background="White"
HorizontalAlignment="Center">
<StackPanel Orientation="Horizontal">
<StackPanel Orientation="Horizontal">
<TextBox MaxLength="2" TabIndex="0" Style="{StaticResource BirthDDTextBoxStyle}"
Text="{Binding BirthDay,Mode=TwoWay,ValidatesOnNotifyDataErrors=True, NotifyOnValidationError=True}"/>
<TextBlock Style="{StaticResource TextBlockStyle_DateSeperator}"/>
<TextBox MaxLength="2" TabIndex="1" Style="{StaticResource BirthDDTextBoxStyle}" Text="{Binding BirthMonth, Mode=TwoWay,ValidatesOnNotifyDataErrors=True, NotifyOnValidationError=True}"/>
<TextBlock Style="{StaticResource TextBlockStyle_DateSeperator}"/>
<TextBox MaxLength="4" TabIndex="2" Style="{StaticResource BirthYYTextBoxStyle}" Text="{Binding BirthYear, Mode=TwoWay, ValidatesOnNotifyDataErrors=True, NotifyOnValidationError=True}"/>
<Button Content="Show" Width="100" Height="30" Click="Button_Click"/>
</StackPanel>
</StackPanel>
</Grid>
</UserControl>
DateControlViewModel :
namespace DatePicker
{
public class DatePickerViewModel : EntityViewModel
{
public DatePickerViewModel()
{
}
private DateTime birthDate;
public DateTime BirthDate
{
get
{
return birthDate;
}
set
{
birthDate = value;
}
}
private string birthDay;
public string BirthDay
{
get { return birthDay; }
set
{
birthDay = value;
PropertyChangedHandler("BirthDay");
ValidateBirthDay("BirthDay", value);
}
}
private string birthMonth;
public string BirthMonth
{
get { return birthMonth; }
set
{
birthMonth = value;
PropertyChangedHandler("BirthMonth");
ValidateBirthMonth("BirthMonth", value);
}
}
private string birthYear;
public string BirthYear
{
get { return birthYear; }
set
{
birthYear = value;
PropertyChangedHandler("BirthYear");
ValidateBirthYear("BirthYear", value);
}
}
private void ValidateDOB()
{
ClearErrorFromProperty("BirthDay");
ClearErrorFromProperty("BirthMonth");
ClearErrorFromProperty("BirthYear");
if (string.IsNullOrEmpty(BirthDay))
ValidateBirthDay("BirthDay", BirthDay);
if (string.IsNullOrEmpty(BirthMonth))
ValidateBirthMonth("BirthMonth", BirthMonth);
if (string.IsNullOrEmpty(BirthYear))
ValidateBirthYear("BirthYear", BirthYear);
if (!string.IsNullOrEmpty(BirthDay) && !string.IsNullOrEmpty(BirthMonth) && !string.IsNullOrEmpty(BirthYear))
SetDateOfBirth();
}
private void ValidateBirthDay(string propertyName, string value)
{
ClearErrorFromProperty(propertyName);
if (String.IsNullOrEmpty(value))
AddErrorForProperty(propertyName, "Resources.PatientImport.EmptyDayMessage");
else
if (Common.IsNumber(value))
{
int day = Convert.ToInt32(value);
if (day > 31 || day < 1)
AddErrorForProperty(propertyName, "Resources.PatientImport.InvalidDayMessage");
}
else
AddErrorForProperty(propertyName, "Resources.PatientImport.InvalidDayMessage");
}
private void ValidateBirthMonth(string propertyName, string value)
{
ClearErrorFromProperty(propertyName);
if (String.IsNullOrEmpty(value))
AddErrorForProperty(propertyName, "Resources.PatientImport.EmptyMonthMessage");
else
if (Common.IsNumber(value))
{
int month = Convert.ToInt32(value);
if (month > 12 || month < 1)
AddErrorForProperty(propertyName, "Resources.PatientImport.InvalidMonthMessage");
}
else
AddErrorForProperty(propertyName, "Resources.PatientImport.InvalidMonthMessage");
}
private void ValidateBirthYear(string propertyName, string value)
{
ClearErrorFromProperty(propertyName);
if (String.IsNullOrEmpty(value))
AddErrorForProperty(propertyName, "Resources.PatientImport.EmptyYearMessage");
else
if (Common.IsNumber(value))
{
int year = Convert.ToInt32(value);
if (year.ToString().Length > 4 || year.ToString().Length < 4)
AddErrorForProperty(propertyName, "Resources.PatientImport.InvalidYearMessage");
}
else
AddErrorForProperty(propertyName, "Resources.PatientImport.InvalidYearMessage");
}
private void SetDateOfBirth()
{
string dateString = BirthDay + "-" + BirthMonth + "-" + BirthYear;
DateTime date;
if (!DateTime.TryParse(dateString.ToString(), out date))
{
ClearErrorFromProperty("BirthDay");
ClearErrorFromProperty("BirthMonth");
ClearErrorFromProperty("BirthYear");
AddErrorForProperty("BirthDay", "Resources.PatientImport.InvalidDayMessage");
AddErrorForProperty("BirthMonth", "Resources.PatientImport.InvalidMonthMessage");
AddErrorForProperty("BirthYear", "Resources.PatientImport.InvalidYearMessage");
}
else
BirthDate = date;
}
}
}
我想在 MainPage.xaml :
中使用此控件<UserControl x:Class="DatePicker.MainPage"
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:DatePicker"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="400">
<Grid x:Name="LayoutRoot" Background="White">
<local:DateControl />
</Grid>
</UserControl>
我想在DateControl中定义一个Property,我将用它将UserControl与MainPage.xaml的ViewModel绑定
类似的东西:
<Grid x:Name="LayoutRoot" Background="White">
<local:DateControl Date="{Binding BirthDate, Mode=TwoWay, ValidatesOnNotifyDataErrors=True, NotifyOnValidationError=True}"/>
</Grid>
BirthDate是字符串类型属性。
如何更改我的usercontrol,以便我可以使用单独的MVVM在MainPage.XAML中绑定其属性
答案 0 :(得分:1)
首先,您需要将DataContex
的{{1}} t设置为DateControl
。在DateControlViewModel
xaml中,您可以使用此构思,或者将其设置在代码中的某个位置(如DateControl
的构造函数),或者将DateControl
数据绑定到要使用的视图模型。
DataContext
其次,您需要在 <UserControl.Resources>
<viewModels:ViewDisplayTemplatesViewModel x:Key="viewModel" />
</UserControl.Resources>
<UserControl.DataContext>
<Binding Source="{StaticResource viewModel}"/>
</UserControl.DataContext>
中定义依赖项属性,就像评论中提到的Aardvark一样。我使用了propdp片段(我认为它随Silverlight安装一起提供,如果没有,你可以在这个MSDN article中看到它)。 Dependency属性启用xaml中的绑定。