我的XAML：
<TextBox Text="{x:Bind local:Amount, Converter={StaticResource VolumeConverter}, Mode=TwoWay}"/>
<ComboBox x:Name="ComboBox_Amount_Unit" />
如何将ComboBox_Amount_Unit的选定索引作为参数传递给TextBox的转换器？
答案 0 :(得分：1)
感谢Shakir Ahmed花费的时间帮助我提供解决方案。我几个小时前才找到解决方案：
private double _BrewAmount = 10;
public double BrewAmount
{
get { return _BrewAmount; }
set
{
CorrectedBrewAmount = value.ToString();
}
} // In database. Holds the volume in liters, no matter the ComboBox unit selection.
private string _CorrectedBrewAmount = "0";
public string CorrectedBrewAmount
{
get
{
string[] Result = Convert.VolumeFromLiterWithUnitConversion(BrewAmount, BrewAmountSelectedIndex == -1 ? AppSettings.MeasuringSystem == MeasuringSystem.Systems[MeasuringSystem.Metric] ? LiquidUnit.Liter : LiquidUnit.Gallon : BrewAmountSelectedIndex);
_CorrectedBrewAmount = Result[0];
return Result[0];
}
set
{
_BrewAmount = Convert.VolumeToLiter(System.Convert.ToDouble(value), BrewAmountSelectedIndex == -1 ? AppSettings.MeasuringSystem == MeasuringSystem.Systems[MeasuringSystem.Metric] ? LiquidUnit.Liter : LiquidUnit.Gallon : BrewAmountSelectedIndex);
NotifyPropertyChanged("CorrectedBrewAmount");
}
} // Not in database. The value shown in the TextBox.
private int _BrewAmountSelectedIndex = -1;
public int BrewAmountSelectedIndex
{
get
{
return _BrewAmountSelectedIndex;
}
set
{
_BrewAmountSelectedIndex = value;
_BrewAmount = Convert.VolumeToLiter(System.Convert.ToDouble(_CorrectedBrewAmount), value == -1 ? LiquidUnit.Liter : value);
NotifyPropertyChanged("BrewAmountSelectedIndex");
}
} // Not in database. The bindable selected index.
我有一些转换器作为函数，并且使用了在UI中显示和绑定的更正属性，而“真实”值在原始属性中。它看起来很复杂，但是却可以正常工作。您会看到CorrectedBrewAmount和BrewAmountSelectedindex正在设置_BrewAmount，以使BrewAmount的设置器（不带下划线）不会触发。然后，通过代码设置BrewAmount时，则会设置CorrectedBrewAmount来触发转换。
答案 1 :(得分：0)
希望对您有所帮助（未经测试）：
<TextBox x:Name="myTextbox" Text="{x:Bind local:Amount, Converter={StaticResource VolumeConverter},ConverterParameter={Binding ElementName=ComboBox_Amount_Unit,Path=SelectedIndex}, Mode=TwoWay />
<ComboBox x:Name="ComboBox_Amount_Unit" }" />
答案 2 :(得分：0)
这是达成目标的另一种方法：
<Page
x:Class="App12.BlankPage2"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:App12"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Page.Resources>
<local:VolumeConverter x:Key="cvt"/>
</Page.Resources>
<Grid>
<StackPanel VerticalAlignment="Center"
HorizontalAlignment="Center">
<TextBox PlaceholderText="Input value in meter"
Width="300"
Text="{x:Bind InputValue, Mode=TwoWay}"/>
<Button Content="Calculate" Click="Button_Click"/>
<ComboBox x:Name="ComboBox_Amount_Unit"
Margin="0,30,0,0"
Loaded="ComboBox_Amount_Unit_Loaded">
<ComboBox.Items>
<ComboBoxItem Content="mm"/>
<ComboBoxItem Content="cm"/>
<ComboBoxItem Content="M"/>
<ComboBoxItem Content="kM"/>
</ComboBox.Items>
</ComboBox>
<TextBlock Name="outputTextBlock"
FontSize="25"
Text="{x:Bind Volume, Mode=OneWay, Converter={StaticResource cvt}}"/>
</StackPanel>
</Grid>
</Page>
public sealed partial class BlankPage2 : Page, INotifyPropertyChanged
{
public static BlankPage2 Current;
public BlankPage2()
{
this.InitializeComponent();
Current = this;
}
double _volume;
int _inputValue;
public double Volume
{
get { return _volume; }
set { _volume = value; RaisePropertyChanged(); }
}
public int InputValue
{
get { return _inputValue; }
set { _inputValue = value; }
}
public int getIndex()
{
return ComboBox_Amount_Unit.SelectedIndex;
}
public event PropertyChangedEventHandler PropertyChanged;
void RaisePropertyChanged([CallerMemberName]string name = null)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(name));
}
}
private void ComboBox_Amount_Unit_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if ((sender as ComboBox).SelectedIndex == 0)
{
Volume = InputValue * 1000000000;
}
else if ((sender as ComboBox).SelectedIndex == 1)
{
Volume = InputValue * 1000000;
}
else if ((sender as ComboBox).SelectedIndex == 2)
{
Volume = InputValue;
}
else if ((sender as ComboBox).SelectedIndex == 3)
{
Volume = InputValue / 1000000000;
}
else Volume = InputValue;
}
private void ComboBox_Amount_Unit_Loaded(object sender, RoutedEventArgs e)
{
ComboBox_Amount_Unit.SelectedIndex = 0;
ComboBox_Amount_Unit.SelectionChanged += ComboBox_Amount_Unit_SelectionChanged;
}
private void Button_Click(object sender, RoutedEventArgs e)
{
if (ComboBox_Amount_Unit.SelectedIndex == 0)
{
Volume = InputValue * 1000000000;
}
else if (ComboBox_Amount_Unit.SelectedIndex == 1)
{
Volume = InputValue * 1000000;
}
else if (ComboBox_Amount_Unit.SelectedIndex == 2)
{
Volume = InputValue;
}
else if (ComboBox_Amount_Unit.SelectedIndex == 3)
{
Volume = InputValue / 1000000000;
}
else Volume = InputValue;
}
}
public class VolumeConverter: IValueConverter
{
public object Convert(object value, Type targetType, object parameter, string language)
{
double val = (double)value;
if (val == 0.0) return "";
int index = BlankPage2.Current.getIndex();
if(index == 0)
{
return val.ToString() + " " + "mm";
}
else if(index == 1)
{
return val.ToString() + " " + "cm";
}
else if(index == 2)
{
return val.ToString() + " " + "m";
}
else if (index == 3)
{
return val.ToString() + " " + "km";
}
return val.ToString();
}
public object ConvertBack(object value, Type targetType, object parameter, string language)
{
throw new NotImplementedException();
}
}