IsNullOrEmpty(string)和List.数比;0美元的胡须

本文关键字：美元胡须数比 List string IsNullOrEmpty | 更新日期: 2023-09-27 17:52:33

我使用mustache-sharp作为模板引擎

我想知道是否有使用这个模板引擎，并有两个条件来检查

1) IsNullOrEmpty(string)  => e.g. {{#IsNullOrEmpty MyName}}} {{/IsNullOrEmpty}}
2) List.Count > 0         => e.g. {{#Any Persons}} {{/Any}}

谁能指导我如何创建像上面这样的标签?

IsNullOrEmpty(string)和List.数比;0美元的胡须

你可以尝试创建一个自定义的ContentTagDefinition并注册到HtmlFormatCompiler。

例如:

IsNullOrEmpty

public class IsNullOrEmptyTagDefinition : ContentTagDefinition
{
    private const string conditionParameter = "condition";
    public IsNullOrEmptyTagDefinition()
        : base("IsNullOrEmpty")
    {}
    public override IEnumerable<TagParameter> GetChildContextParameters()
    {
        return new TagParameter[0];
    }
    public override bool ShouldGeneratePrimaryGroup(Dictionary<string, object> arguments)
    {
        object condition = arguments[conditionParameter];
        return isConditionSatisfied(condition);
    }
    protected override IEnumerable<TagParameter> GetParameters()
    {
        return new TagParameter[] { new TagParameter(conditionParameter) { IsRequired = true } };
    }
    protected override bool GetIsContextSensitive()
    {
        return false;
    }
    private bool isConditionSatisfied(object condition)
    {
        if (condition == null)
        {
            return true;
        }
        return condition is string ? string.IsNullOrEmpty(condition as string) : false;
    }
}

public class AnyTagDefinition : ContentTagDefinition
{
    private const string conditionParameter = "condition";
    public AnyTagDefinition()
        : base("Any")
    {}
    public override IEnumerable<TagParameter> GetChildContextParameters()
    {
        return new TagParameter[0];
    }
    public override bool ShouldGeneratePrimaryGroup(Dictionary<string, object> arguments)
    {
        object condition = arguments[conditionParameter];
        return isConditionSatisfied(condition);
    }
    protected override IEnumerable<TagParameter> GetParameters()
    {
        return new TagParameter[] { new TagParameter(conditionParameter) { IsRequired = true } };
    }
    protected override bool GetIsContextSensitive()
    {
        return false;
    }
    private bool isConditionSatisfied(object condition)
    {
        if (condition is IEnumerable)
        {
            return (condition as IEnumerable).Cast<object>().Any();
        }
        return false;
    }
}

注册两个标签

HtmlFormatCompiler compiler = new HtmlFormatCompiler();
compiler.RegisterTag(new IsNullOrEmptyTagDefinition(), true);
compiler.RegisterTag(new AnyTagDefinition(), true);