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？
解决方法
您可以使用表达式来获取编译器检查的绑定.
例如,在当前的一个项目中,我们设置了这样的绑定：
例如,在当前的一个项目中,我们设置了这样的绑定：
DataBinder
.BindToObject(this)
.ObjectProperty(c => c.IsReadOnly)
.Control(nameTextBox,n => n.ReadOnly)
.Control(addressControl,n => n.ReadOnly)
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());
}
}
