Question

在获得所选的Combobox值时遇到问题。我得到的错误是，我似乎无法解决它，尝试了各种绑定，选择值路径等组合，希望有人可以指出我正确的方向，谢谢！

ConvertBack无法转换值'ClientRatesWPF.Model.ChargeUnit' （输入'ChargeUnit'）。 BindingExpression：路径= SelectedChargeUnitListValueId; DataItem ='ClientRatesViewModel'（HashCode = 33434731）;目标元素是 'ComboBox'（Name ='cmbChargeUnit'）; target属性是'SelectedValue' （类型'Object'）NotSupportedException：'System.NotSupportedException： Int32Converter无法从ClientRatesWPF.Model.ChargeUnit转换。

<av:ComboBox x:Name="cmbChargeUnit" HorizontalAlignment="Left" Margin="548,15,0,0" Width="187" ItemsSource="{av:Binding ChargeUnits}" DisplayMemberPath="ChargeUnitDescription" SelectedValue="{Binding SelectedChargeUnitListValueId}" VerticalAlignment="Top" Background="{av:DynamicResource {x:Static av:SystemColors.ControlDarkDarkBrushKey}}" Height="20" IsSynchronizedWithCurrentItem="True"/>

VM：

public ObservableCollection<ChargeUnit> ChargeUnits
{
    get { return _chargeUnitsCollection; }
    set { _chargeUnitsCollection = value; }
}

public IList<ChargeUnit> ChargeUnitDescription
{
    get { return _chargeUnitDescription; }
    set
    {
        _chargeUnitDescription = value;
        OnPropertyChanged("ChargeUnitDescription");
    }
}

public IList<ChargeUnit> ChargeUnitListValueId
{
    get { return _chargeUnitListValueId; }
    set
    {
        _chargeUnitListValueId = value;
        OnPropertyChanged("ChargeUnitListValueId");
    }
}

public int SelectedChargeUnitListValueId
{
    get { return _SelectedChargeUnitListValueId; }
    set
    {
        _SelectedChargeUnitListValueId = value;
        OnPropertyChanged("SelectedChargeUnitListValueId");
    }
}

我填充Observable Collection的地方（从方法中提取的代码）

while (reader.Read())
{
    _chargeUnitsCollection.Add(new ChargeUnit
    {
        ChargeUnitListValueId = (int)reader["ListValueId"],
        ChargeUnitDescription = reader["ValueName"].ToString()
    });
}

Answer 1

所以你有一个填充了ChargeUnit列表的组合框，并且你试图将SelectedValue设置为int，这将是你的问题。您需要更改为所选的ChargeUnit

public int SelectedChargeUnitListValueId
{
    get { return _SelectedChargeUnitListValueId; }
    set
    {
        _SelectedChargeUnitListValueId = value;
        var unitsWhere = ChargeUnits.Where(x => x.id == _SelectedChargeUnitListValueId);
        if (unitsWhere.Count() > 0)
        {
           SelectedChargeUnit = unitsWhere.First();
        }
        OnPropertyChanged("SelectedChargeUnitListValueId");
    }
}

public ChargeUnit SelectedChargeUnit
{
    get { return _SelectedChargeUnit; }
    set
    {
        _SelectedChargeUnit = value;
        OnPropertyChanged("SelectedChargeUnit");
    }
}

并在你的装订中：

SelectedValue="{Binding SelectedChargeUnit}"

Combobox Binding MVVM WPF SelectedValue

1 个答案: