c# - 如何在 C# 中的 FontWeights 之间使用等于运算符？

Question

我必须在我的 CustomControl 中创建一个 FontWeight 属性，但它在控制 FontWeights 时出错。我该如何解决？

属性(property)登记:

public static readonly DependencyProperty FontWeightProperty =
        DependencyProperty.Register(
            "FontWeight",
            typeof(int),
            typeof(WatermarkTextBox),
        new PropertyMetadata(0));

Property(我们可以改变这个属性，这是我的业余工作):

    private int _watermarkFontWeight = 0;

    public int WatermarkFontWeight
    {
        get
        {
            if (watermarkPassTextBox.FontWeight == FontWeights.Normal)
            {
                _watermarkFontWeight = 0;
            }
            else if (watermarkPassTextBox.FontWeight == FontWeights.SemiBold)
            {
                _watermarkFontWeight = 1;
            }
            else if (watermarkPassTextBox.FontWeight == FontWeights.Bold)
            {
                _watermarkFontWeight = 2;
            }
            else if (watermarkPassTextBox.FontWeight == FontWeights.ExtraBold)
            {
                _watermarkFontWeight = 3;
            }
            return _watermarkFontWeight;
        }
        set
        {
            if (value == 0)
            {
                SetProperty<int>(ref _watermarkFontWeight, value, "FontWeight");
                watermarkPassTextBox.FontWeight = FontWeights.Normal;
            }
            else if (value == 1)
            {
                SetProperty<int>(ref _watermarkFontWeight, value, "FontWeight");
                watermarkPassTextBox.FontWeight = FontWeights.SemiBold;
            }
            else if (value == 2)
            {
                SetProperty<int>(ref _watermarkFontWeight, value, "FontWeight");
                watermarkPassTextBox.FontWeight = FontWeights.Bold;
            }
            else if (value == 3)
            {
                SetProperty<int>(ref _watermarkFontWeight, value, "FontWeight");
                watermarkPassTextBox.FontWeight = FontWeights.ExtraBold;
            }
        }
    }

错误:

Operator '==' cannot be applied to operands of type 'Windows.UI.Text.FontWeight' and 'Windows.UI.Text.FontWeight'

谢谢。

Answer 1

从 documentation page 中我可以看出(这令人惊讶地缺乏信息和/或我无法找到详细的 decoumentation)，FontWeight 是一个 struct 值类型，不为 == 定义一个运算符，这样你就不能直接比较它们。

但是，我认为您可以比较它们的底层包装 Weight 值:

if (watermarkPassTextBox.FontWeight.Weight == FontWeights.Normal.Weight)

编辑:我不确定他们的 Equals 实现是否有效(同样，可爱的文档)，但您可以创建一个扩展方法来为您提供一些看起来不错的语法:

public static bool Equals(this FontWeight weight1, FontWeight weight2)
{
    return weight1.Weight == weight2.Weight;
}

这导致使用:

if (watermarkPassTextBox.FontWeight.Equals(FontWeights.Normal))
    _watermarkFontWeight = 0;
else if (watermarkPassTextBox.FontWeight.Equals(FontWeights.SemiBold))
    _watermarkFontWeight = 1;
else if (watermarkPassTextBox.FontWeight.Equals(FontWeights.Bold))
    _watermarkFontWeight = 2;
else if (watermarkPassTextBox.FontWeight.Equals(FontWeights.ExtraBold))
    _watermarkFontWeight = 3;
else
    return _watermarkFontWeight;