有没有办法让C#绑定工作静态？

Question

这可能适用于其他地方,但在WinForms中,当我使用绑定时,我发现许多方法都希望将属性的名称绑定到.就像是:

class Person
{
    public String Name { get { ... } set { ... } }
    public int Age { get { ... } set { ... } }
}

class PersonView
{
    void Bind(Person p)
    {
        nameControl.Bind(p,"Name");
        ageControl.Bind(p,"Age");
    }
}

我一直遇到的一个大问题是"Name"和"Age"被指定为字符串.这意味着如果有人重命名Person的一个属性,编译器就无济于事.代码编译正常,但绑定将被破坏.

我错过了解决这个问题的标准方法吗？感觉我需要一些关键字,也许叫做stringof来匹配现有的typeof.你可以使用它:

ageControl.Bind(p,stringof(p.Age).Name);

stringof可以返回一些具有获取完整路径,路径的一部分或字符串的属性的类,以便您可以自己解析它.

这样的事情已经可以吗？

Answer 1

您可以使用表达式来获取经过编译器检查的绑定。例如，在当前的项目之一中，我们设置如下绑定：

DataBinder
    .BindToObject(this)
    .ObjectProperty(c => c.IsReadOnly)
        .Control(nameTextBox, n => n.ReadOnly)
        .Control(addressControl, n => n.ReadOnly)

支持这种风格的代码分为几个类：

public static class DataBinder
{
    public static DataBinderBindingSourceContext<TDataSource> BindToObject<TDataSource>(TDataSource dataSource)
    {
        return new DataBinderBindingSourceContext<TDataSource>(dataSource);
    }
}

public class DataBinderBindingSourceContext<TDataSource> 
{
    public readonly object DataSource;

    public DataBinderBindingSourceContext(object dataSource)
    {
        DataSource = dataSource;
    }

    public DataBinderControlContext<TDataSource, TProperty> ObjectProperty<TProperty>(Expression<Func<TDataSource, TProperty>> property)
    {
        return new DataBinderControlContext<TDataSource, TProperty>(this, property);
    }
}

public class DataBinderControlContext<TDataSource, TProperty>
{
    readonly DataBinderBindingSourceContext<TDataSource> BindingSourceContext;
    readonly string ObjectProperty;

    public DataBinderControlContext
        (
            DataBinderBindingSourceContext<TDataSource> bindingSourceContext,
            Expression<Func<TDataSource, TProperty>> objectProperty
        )
    {
        BindingSourceContext = RequireArg.NotNull(bindingSourceContext);
        ObjectProperty = ExpressionHelper.GetPropertyName(objectProperty);
    }

    public DataBinderControlContext<TDataSource, TProperty> Control<TControl>(TControl control, Expression<Func<TControl, TProperty>> property)
        where TControl : Control
    {
        var controlPropertyName = ExpressionHelper.GetPropertyName(property);
        control.DataBindings.Add(controlPropertyName, BindingSourceContext.DataSource, ObjectProperty, true);

        return this;
    }
}

public static class ExpressionHelper
{
    public static string GetPropertyName<TResult>(Expression<Func<TResult>> property)
    {
        return GetMemberNames(((LambdaExpression)property).Body).Skip(1).Join(".");
    }

    public static string GetPropertyName<T, TResult>(Expression<Func<T, TResult>> property)
    {
        return GetMemberNames(((LambdaExpression)property).Body).Join(".");
    }

    static IEnumerable<string> GetMemberNames(Expression expression)
    {
        if (expression is ConstantExpression || expression is ParameterExpression)
            yield break;

        var memberExpression = (MemberExpression)expression;

        foreach (var memberName in GetMemberNames(memberExpression.Expression))
            yield return memberName;

        yield return memberExpression.Member.Name;
    }
}

public static class StringExtentions
{
    public static string Join(this IEnumerable<string> values, string separator)
    {
        if (values == null)
            return null;

        return string.Join(separator, values.ToArray());
    }
}