验证输入WPF DataGrid

Question

我试图验证在WPF中的Datagrid中输入的输入。

我已经向XAML添加了验证规则。

输入不再是对象，而是字符串或整数。 虽然我使用的方法期望一个对象。

我如何解决该问题并使它与int或字符串一起工作。 输入只能是1到20之间的一个整数。

XAML ：

<DataGridTextColumn Header="Niveau">                                
    <DataGridTextColumn.Binding>                                                                 
        <Binding Path="Niveau" UpdateSourceTrigger="LostFocus">
            <Binding.ValidationRules>                                       
                <valRule:NiveautredeValidationRule  />                                             
            </Binding.ValidationRules>
        </Binding>                                          
    </DataGridTextColumn.Binding>                                               
</DataGridTextColumn>

C＃

public class NiveautredeValidationRule : ValidationRule
{
    public override System.Windows.Controls.ValidationResult Validate(object value, System.Globalization.CultureInfo cultureInfo)
    {
        NiveaudoelenViewModel doel = (value as BindingGroup).Items[0] as NiveaudoelenViewModel;
        if (doel.Niveau <= 0 || doel.Niveau > 20)
        {
            return new System.Windows.Controls.ValidationResult(false, "Niveau moet tussen de 1 en 20 zijn!");
        }
        else
        {
            return System.Windows.Controls.ValidationResult.ValidResult;
        }
    }
}

Answer 1

您可以尝试以下方法：

public override System.Windows.Controls.ValidationResult Validate(object value, 
    System.Globalization.CultureInfo cultureInfo)
{
    int myInt = 0;

    try
    {
        if (((string)value).Length > 0)
            myInt = int.Parse((String)value);
    }
    catch (Exception e)
    {
        return new ValidationResult(false, "Illegal characters or " + e.Message);
    }

    if (myInt < 0 || myInt > 20)
    {
        return new ValidationResult(false,
          "Please enter a number in the range: 0 - 20");
    }
    else
    {
        return new ValidationResult(true, null);
    }
}

来源： https : //docs.microsoft.com/zh-cn/dotnet/framework/wpf/data/how-to-implement-binding-validation

Answer 2

您应该考虑更新对此的可接受答案，这消除了try catch并改用TryParse

public override System.Windows.Controls.ValidationResult Validate(object value, 
    System.Globalization.CultureInfo cultureInfo)
{
    int myInt;
    if (!int.TryParse(System.Convert.ToString(value), out myInt))
        return new ValidationResult(false, "Illegal characters");

    if (myInt < 0 || myInt > 20)
    {
        return new ValidationResult(false, "Please enter a number in the range: 0 - 20");
    }
    else
    {
        return new ValidationResult(true, null);
    }
}