Handlebars.Net If条件帮助器

Question

我试着写一个Handlebar.Net帮助器，它的工作方式与Equals相同。Helper应该像这样使用

{{#eq name "Foo"}}
    true
{{else}}
    false
{{/eq}}

但是我不知道如何实现这个帮助器。在JS中有this示例，但我找不到C#的示例。

我的第一个镜头是：

Handlebars.RegisterHelper("#eq", (output, context, data) =>
{
    if (data.Length != 2)
        output.WriteSafeString("false");

    output.WriteSafeString(data[0].Equals(data[1]));
});

但这只是将True或False写入到我的文件中。

Answer 1

我已经找到了解决方案：

Handlebars.RegisterHelper(Equals, (output, options, context, data) => 
{
    if (data.Length != 2)
        options.Inverse(output, null);

    if (data[0].Equals(data[1]))
        options.Template(output, null);
    else
        options.Inverse(output, null);
});
Handlebars.RegisterHelper(LowerThan, (output, options, context, data) =>
{
    IntegerOperation(LowerThan, ref output, ref options, ref data);
});

Handlebars.RegisterHelper(GreaterThan, (output, options, context, data) =>
{
    IntegerOperation(GreaterThan, ref output, ref options, ref data);
});

Handlebars.RegisterHelper(LowerEquals, (output, options, context, data) =>
{
    IntegerOperation(LowerEquals, ref output, ref options, ref data);
});

Handlebars.RegisterHelper(GreaterEquals, (output, options, context, data) =>
{
    IntegerOperation(GreaterEquals, ref output, ref options, ref data);
});


private static void IntegerOperation(string operation, ref System.IO.TextWriter output, ref HelperOptions options, ref object[] data)
{
    if (data.Length != 2)
    {
        options.Inverse(output, null);
        return;
    }

    if (!int.TryParse(data[0].ToString(), out int leftValue))
    {
        options.Inverse(output, null);
        return;
    }

    if (!int.TryParse(data[1].ToString(), out int rightValue))
    {
        options.Inverse(output, null);
        return;
    }

    switch (operation)
    {
        case "lt":
            if (leftValue < rightValue)
                options.Template(output, null);
            else
                options.Inverse(output, null);
            break;
        case "le":
            if (leftValue <= rightValue)
                options.Template(output, null);
            else
                options.Inverse(output, null);
            break;
        case "gt":
            if (leftValue > rightValue)
                options.Template(output, null);
            else
                options.Inverse(output, null);
            break;
        case "ge":
            if (leftValue >= rightValue)
                options.Template(output, null);
            else
                options.Inverse(output, null);
            break;
        default:
            break;
    }