Question

我正在尝试设置属性类的值。

protected bool TryUpdate(PropertyInfo prop, object value)
{
    try
    {
        prop.SetValue(this, value);

        // If not set probably a complex type
        if (value != prop.GetValue(this))
        {
           //... Don't know what to do
        }
        // If still not set update failed
        if (value != prop.GetValue(this))
        {
            return false;
        }
        return true;

    }

}

我在各种类的许多属性上调用此方法。这个问题是我有一个类如下的类：

public class Test
{
    public string Name { get; set; }

    public string Number { get; set; }

    public IComplexObject Object { get; set; }
}

Name和Number设置得很好但是如果我尝试设置一个继承自Object上的IComplexObject的类的实例，则没有错误它只是保持为null。

有没有一种简单的方法可以将类的实例设置为属性？

例如，如果我将prop作为{IComplexObject Object}传递，而将对象传递为

var object = (object) new ComplexObject
{
    prop1 = "Property"
    prop2 = "OtherProperty"
}

最后没有错误，但Object仍然为null，并且未设置为ComplexObject的实例。它必须是通用的，所以我可以传入任何类，并且属性将被更新。

Answer 1

你的代码是不必要的复杂，但它完全正常。我已经把你的代码扩展为一个完整的例子。

输出就是这个。

Name: asdf, Number: A1B2, Object: hello this is complexobject
It was not null

这表明Object属性与其他属性没有区别。 “复杂对象”不是一个真正意味着.net的术语。此外，您对async的使用似乎没有必要且令人困惑。

async void Main() {
    Test t = new Test();
    Type type = typeof(Test);

    await t.TryUpdate(type.GetProperty(nameof(t.Name)), "asdf");
    await t.TryUpdate(type.GetProperty(nameof(t.Number)), "A1B2");
    await t.TryUpdate(type.GetProperty(nameof(t.Object)), (object)new ComplexObject());

    Console.WriteLine(t.ToString());

    PropertyInfo prop = type.GetProperty(nameof(t.Object));

    if (prop.GetValue(t) == null) {
        Console.WriteLine("It was null");
    } else {
        Console.WriteLine("It was not null");
    }
}

public class Test {
    public string Name { get; set; }
    public string Number { get; set; }
    public IComplexObject Object { get; set; }

    // Added for the purpose if showing contents
    public override string ToString() => $"Name: {Name}, Number: {Number}, Object: {Object}";

    // Why is this async?  Your code does not await
    public async Task<bool> TryUpdate(PropertyInfo prop, object value) {
        await Task.Delay(0); // Added to satisfy async
        try {
            prop.SetValue(this, value);

            // If not set probably a complex type
            if (value != prop.GetValue(this)) {
                //... Don't know what to do
            }

            return true;
        }
        catch {
            return false;
        }
    }

}

public interface IComplexObject { }
class ComplexObject : IComplexObject {
    public override string ToString() => "hello this is complexobject";
}

Answer 2

此示例有效。我把它作为参考我已将其更改为等待任务并将返回值提取到结果变量，以便您可以看到它返回true。

public class Test
{
    public string Name { get; set; }

    public string Number { get; set; }

    public IComplexObject Object { get; set; }

    public async Task<bool> TryUpdate(PropertyInfo prop, object value) {
        try {
            prop.SetValue(this, value);
            return true;
        }
        catch (Exception) {

        }

        return false;
    }

}

public class ComplexObject : IComplexObject
{
}

public interface IComplexObject
{

}
static class  Program
{

    static void Main() {
        TestMethod();
    }

    static async void TestMethod() {
        var test = new Test();
        var result = await test.TryUpdate(test.GetType().GetProperty("Object"), new ComplexObject());
    }
}

如何在C＃

2 个答案: