选择器错误“指定的演员表无效"在 Xamarin Forms 中获取 SelectedItem 值时 [英] Picker error "Specified cast is not valid" when getting the SelectedItem value in Xamarin Forms

问题描述

我有一个选择器，已经设置了绑定，但是当我尝试将 selecteditem 值复制到变量时，却显示错误System.InvalidCastException: 'Specified cast is not valid'.所选项目中包含的信息实际上是正确的，这是我的代码:

I have a picker, already set with the bindings, but when I'm trying to copy the selecteditem value to a variable but shows error "System.InvalidCastException: 'Specified cast is not valid'. The info contained in the selected item is actually correct, this is my code:

IDPisteroMainPage = Convert.ToInt32(pck_Pisteros.SelectedItem);

也试过这个(也没有用，抛出了不同的错误):

also tried this (didn't work either, different error thrown tho):

IDPisteroMainPage = Convert.ToInt32(pck_Pisteros.SelectedItem as Pisteros);

Pisteros 是使用的模型.

Pisteros being the model in used.

错误:

我还在 SelectedIndex 上绑定了同一个对象，但是这个对象仍然返回索引而不是我需要的 PisteroID，但是如果我使用以下内容:

Also I have the binding for the same object on SelectedIndex, but this one still returns the index and not the PisteroID which is what I need, but if I use the following:

IDPisteroMainPage = Convert.ToInt32(pck_Pisteros.SelectedIndex);

该值确实可以毫无问题地复制到变量中

the value does gets copied to the variable without issues

推荐答案

很难说出您真正想要什么或涉及的类型.但是，它可能是您正在寻找的.

It's hard to tell what you actually want or the types involved. However, it could be you are looking for.

IDPisteroMainPage = Convert.ToInt32(((Pisteros)pck_Pisteros.SelectedItem).PisteroId);

// or slightly more fault tolerant if you expect a null 
if(pck_Pisteros.SelectedItem is Pisteros pisteros)
   IDPisteroMainPage = pisteros.PisteroId;
else
   // handle null (if need be)
   

// or if PisteroId is an int and SelectedItem is never null
IDPisteroMainPage = ((Pisteros)pck_Pisteros.SelectedItem).PisteroId

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