Question

因此，当我尝试使用textOn和textOff函数创建自定义开关时，我在Xamarin中遇到此错误。我查了一下这个帖子：https://forums.xamarin.com/discussion/26694/problem-creating-custom-renderer。而且仍然无法弄明白。这也是我第一次为Xamarin创建自定义控件，所以我可能犯了一些初学者的错误

以下是我的自定义控件的代码：

[assembly:ExportRenderer(typeof(CustomSwitch), typeof(CustomSwitchRenderer))]

namespace SalesKicker
{
public class CustomSwitch : Android.Widget.Switch
{
    public static readonly BindableProperty TextOnProperty = BindableProperty.Create<CustomSwitch, string>(p => p.TextOn, AppResources.CustomSwitch_DefaultTextOn);
    public static readonly BindableProperty TextOffProperty = BindableProperty.Create<CustomSwitch, string>(p => p.TextOff, AppResources.CustomSwitch_DefaultTextOff);

    public string TxtOn
    {
        get { return (string)GetValue(TextOnProperty); }
        set { SetValue(TextOnProperty, value); }
    }

    public string TxtOff
    {
        get { return (string)GetValue(TextOffProperty); }
        set { SetValue(TextOffProperty, value); }
    }
}

public class CustomSwitchRenderer : SwitchRenderer
{
//the error is being thrown here: Error CS0115: 'CustomSwitchRenderer.OnElementChanged(ElementChangedEventArgs<CustomSwitch>)': no suitable method found to override (CS0115) (SalesKicker.Droid)
    protected override void OnElementChanged(ElementChangedEventArgs<SalesKicker.CustomSwitch> e)
    {
        base.OnElementChanged(e);

        if (e.OldElement != null || this.Element == null)
        {
            return;
        }

        var customSwitch = this.Element;

        var control = new Switch(Forms.Context)
            {
                TextOn = customSwitch.TxtOn,
                TextOff = customSwitch.TxtOff
            };

        this.SetNativeControl(control);
    }
}
}

有人可以告诉我这里我做错了吗？

Answer 1

参数的类型是function signature的一部分。如果覆盖功能，则必须具有相同的签名。使用ElementChangedEventArgs<Switch>。

protected override void OnElementChanged(ElementChangedEventArgs<Switch> e)

Answer 2

尝试更改为此

using System;
using Xamarin.Forms;
namespace SalesKicker
{
public class CustomSwitch : Switch
{
public static readonly BindableProperty TextOnProperty = BindableProperty.Create<CustomSwitch, string>(p => p.TextOn, AppResources.CustomSwitch_DefaultTextOn);
public static readonly BindableProperty TextOffProperty = BindableProperty.Create<CustomSwitch, string>(p => p.TextOff, AppResources.CustomSwitch_DefaultTextOff);

public string TxtOn
{
    get { return (string)GetValue(TextOnProperty); }
    set { SetValue(TextOnProperty, value); }
}

public string TxtOff
{
    get { return (string)GetValue(TextOffProperty); }
    set { SetValue(TextOffProperty, value); }
}
}
}

Xamarin.Forms项目中的这个类

然后，

[assembly:ExportRenderer(typeof(CustomSwitch), typeof(CustomSwitchRenderer))]
namespace SalesKicker
{
public class CustomSwitchRenderer : SwitchRenderer
{
//the error is being thrown here: Error CS0115: 'CustomSwitchRenderer.OnElementChanged(ElementChangedEventArgs<CustomSwitch>)': no suitable method found to override (CS0115) (SalesKicker.Droid)
protected override void OnElementChanged(ElementChangedEventArgs<Switch> e)
{
    base.OnElementChanged(e);

    if (e.OldElement != null || this.Element == null)
            return;

    var customSwitch = this.Element;

    var control = new Switch(Forms.Context)
        {
            TextOn = customSwitch.TextOn,
            TextOff = customSwitch.TextOff
        };

    this.SetNativeControl(control);
}
}
}

这在Android项目中。如果您有任何进一步的问题，请告诉我。这应该适合你。

Xamarin - 自定义渲染器找不到合适的方法来覆盖

2 个答案: