HandleBars .Net如果比较

Question

我将Handlebars .NET用于邮件模板，因此我在服务器端宽度ASP.NET MVC上生成模板。我需要这样的比较。但这行不通吗？我能做什么？

//Product.ProdType is a enum property 

{{#if (Product.ProdType=='BlaBlaBla')}}
<p>This is a test</p>
{{/if}}

Answer 1

我遇到了同样的问题，并创建了一个可用于数字数据类型和字符串的辅助函数“ ifCond”。可以对其进行优化或扩展以与其他类型一起使用。

Handlebars.RegisterHelper("ifCond",
        (writer, context, args) =>
        {
            if (args.Length != 5)
            {
                writer.Write("ifCond:Wrong number of arguments");
                return;
            }

            if (args[0] == null || args[0].GetType().Name == "UndefinedBindingResult")
            {
                writer.Write("ifCond:args[0] undefined");
                return;
            }
            if (args[1] == null || args[1].GetType().Name == "UndefinedBindingResult")
            {
                writer.Write("ifCond:args[1] undefined");
                return;
            }
            if (args[2] == null || args[2].GetType().Name == "UndefinedBindingResult")
            {
                writer.Write("ifCond:args[2] undefined");
                return;
            }

            if (args[0].GetType().Name == "String")
            {
                string val1 = args[0].ToString();
                string val2 = args[2].ToString();

                switch (args[1].ToString())
                {
                    case ">":
                        writer.Write(val1.Length > val2.Length ? args[3] : args[4]);
                        break;
                    case "=":
                    case "==":
                        writer.Write(val1 == val2 ? args[3] : args[4]);
                        break;
                    case "<":
                        writer.Write(val1.Length < val2.Length ? args[3] : args[4]);
                        break;
                    case "!=":
                    case "<>":
                        writer.Write(val1 != val2 ? args[3] : args[4]);
                        break;
                }
            }
            else
            {
                float val1 = float.Parse(args[0].ToString());
                float val2 = float.Parse(args[2].ToString());

                switch (args[1].ToString())
                {
                    case ">":
                        writer.Write(val1 > val2 ? args[3] : args[4]);
                        break;
                    case "=":
                    case "==":
                        writer.Write(val1 == val2 ? args[3] : args[4]);
                        break;
                    case "<":
                        writer.Write(val1 < val2 ? args[3] : args[4]);
                        break;
                    case "<=":
                        writer.Write(val1 <= val2 ? args[3] : args[4]);
                        break;
                    case ">=":
                        writer.Write(val1 >= val2 ? args[3] : args[4]);
                        break;
                    case "!=":
                    case "<>":
                        writer.Write(val1 != val2 ? args[3] : args[4]);
                        break;
                }
            }

这是一些单元测试，解释了用法：

var template = Handlebars.Compile("{{{ifCond test '>' 1 '>1' '<=1' }}}");
var data = new { test = 2 };
var result = template(data);
Assert.AreEqual(">1", result);

data = new { test = 0 };
result = template(data);
Assert.AreEqual("<=1", result);

template = Handlebars.Compile("{{{ifCond test '=' 1 'eq' 'not eq' }}}");
data = new { test = 1 };
result = template(data);
Assert.AreEqual("eq", result);

data = new { test = 0 };
result = template(data);
Assert.AreEqual("not eq", result);

template = Handlebars.Compile("{{{ifCond test '!=' 1 'diff' 'eq' }}}");
data = new { test = 2 };
result = template(data);
Assert.AreEqual("diff", result);

template = Handlebars.Compile("{{{ifCond str '!=' '' 'not empty' 'empty' }}}");
var datastr = new { str = "abc" };
result = template(datastr);
Assert.AreEqual("not empty", result);

template = Handlebars.Compile("{{{ifCond str '==' '' 'empty' 'not empty' }}}");
datastr = new { str = "" };
result = template(datastr);
Assert.AreEqual("empty", result);

希望它会有所帮助，并且我也希望更好的实现，更优雅的解决方案有效，但我认为可以以更简洁的方式完成。

这是一个在模板内使用Int32值的用法示例：

Handlebars.RegisterHelper("ifCond",
        (writer, context, args) =>
        {
            if (args.Length != 5)
            {
                writer.Write("ifCond:Wrong number of arguments");
                return;
            }

            if (args[0] == null || args[0].GetType().Name == "UndefinedBindingResult")
            {
                writer.Write("ifCond:args[0] undefined");
                return;
            }
            if (args[1] == null || args[1].GetType().Name == "UndefinedBindingResult")
            {
                writer.Write("ifCond:args[1] undefined");
                return;
            }
            if (args[2] == null || args[2].GetType().Name == "UndefinedBindingResult")
            {
                writer.Write("ifCond:args[2] undefined");
                return;
            }

            if (args[0].GetType().Name == "String")
            {
                string val1 = args[0].ToString();
                string val2 = args[2].ToString();

                switch (args[1].ToString())
                {
                    case ">":
                        writer.Write(val1.Length > val2.Length ? args[3] : args[4]);
                        break;
                    case "=":
                    case "==":
                        writer.Write(val1 == val2 ? args[3] : args[4]);
                        break;
                    case "<":
                        writer.Write(val1.Length < val2.Length ? args[3] : args[4]);
                        break;
                    case "!=":
                    case "<>":
                        writer.Write(val1 != val2 ? args[3] : args[4]);
                        break;
                }
            }
            else
            {
                float val1 = float.Parse(args[0].ToString());
                float val2 = float.Parse(args[2].ToString());

                switch (args[1].ToString())
                {
                    case ">":
                        writer.Write(val1 > val2 ? args[3] : args[4]);
                        break;
                    case "=":
                    case "==":
                        writer.Write(val1 == val2 ? args[3] : args[4]);
                        break;
                    case "<":
                        writer.Write(val1 < val2 ? args[3] : args[4]);
                        break;
                    case "<=":
                        writer.Write(val1 <= val2 ? args[3] : args[4]);
                        break;
                    case ">=":
                        writer.Write(val1 >= val2 ? args[3] : args[4]);
                        break;
                    case "!=":
                    case "<>":
                        writer.Write(val1 != val2 ? args[3] : args[4]);
                        break;
                }
            }

这是一个在模板内使用String值的用法示例：

var template = Handlebars.Compile("{{{ifCond test '>' 1 '>1' '<=1' }}}");
var data = new { test = 2 };
var result = template(data);
Assert.AreEqual(">1", result);

data = new { test = 0 };
result = template(data);
Assert.AreEqual("<=1", result);

template = Handlebars.Compile("{{{ifCond test '=' 1 'eq' 'not eq' }}}");
data = new { test = 1 };
result = template(data);
Assert.AreEqual("eq", result);

data = new { test = 0 };
result = template(data);
Assert.AreEqual("not eq", result);

template = Handlebars.Compile("{{{ifCond test '!=' 1 'diff' 'eq' }}}");
data = new { test = 2 };
result = template(data);
Assert.AreEqual("diff", result);

template = Handlebars.Compile("{{{ifCond str '!=' '' 'not empty' 'empty' }}}");
var datastr = new { str = "abc" };
result = template(datastr);
Assert.AreEqual("not empty", result);

template = Handlebars.Compile("{{{ifCond str '==' '' 'empty' 'not empty' }}}");
datastr = new { str = "" };
result = template(datastr);
Assert.AreEqual("empty", result);

Answer 2

像您尝试执行的逻辑必须位于辅助函数中。您不能将这样的关系运算符直接放入车把模板中。它是故意这样设计的。助手非常容易创建和使用。请参阅http://handlebarsjs.com/#helpers了解更多信息。

hbs.registerHelper("IsSame", function(ProdType) {
 if(ProdType == "BlaBlaBla") {
   $('#HereText').append('<p>This is a test</p>');
    }
});

在模板中执行此操作

<div class="row">
   {{IsSame Product.ProdType}}
</div>

所以在这里您将您的值传递给辅助函数并进行比较..