用于将项目转换和注入到占位符的自定义ExpressionBuilder仅评估一次

Question

我正在尝试编写自定义表达式来将翻译注入到web中，但我在运行时计算时遇到了问题，因为它只在页面开始后计算一次，而不是在刷新或语言更改时进行计算。我的代码：

​

<h2 style="margin-top:0px"><asp:Literal ID="Literal15" runat="server" Text="<%$ Translate:ChooseADataset %>"></asp:Literal></h2>

​

using System;
    using System.CodeDom;
    using System.Globalization;
    using System.Linq;
    using System.Text.RegularExpressions;
    using System.Web;
    using System.Web.Compilation;
    using System.Web.UI;

    [ExpressionPrefix("Translate")]
    [AspNetHostingPermission(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
    public class TranslationExpressionBuilder : ExpressionBuilder
    {
        public override bool SupportsEvaluate
        {
            get
            {
                return true;
            }
        }

        public override CodeExpression GetCodeExpression(BoundPropertyEntry entry, object parsedData, ExpressionBuilderContext context)
        {
           return new CodePrimitiveExpression((string)parsedData);
        }

        public override object EvaluateExpression(object target, BoundPropertyEntry entry, object parsedData, ExpressionBuilderContext context)
        {
            return TranslateAndFill((string)parsedData);
        } 
        public override object ParseExpression(string expression, Type propertyType, ExpressionBuilderContext context)
        {
            bool parsed = false;
            string typeName = null;
            string memberName = null;
            if (!String.IsNullOrEmpty(expression))
            {
                var parts = expression.Split(',').ToList();

                if (parts.Count == 1)
                {
                    memberName = parts[0].Trim();
                }
                else if (parts.Count == 2)
                {
                    typeName = parts[0].Trim();
                    memberName = parts[1].Trim();
                }

                parsed = true;
            }

            if (!parsed)
            {
                throw new HttpException("Invalid Reflect" + $" expression - '{expression}'.");
            }

            return TranslateAndFill(memberName);
        }

        private string TranslateAndFill(string name)
        {
            CultureInfo sCulture = WebHelpers.GetCurrentCultureInfo();

            var manager = new System.Resources.ResourceManager("Resources.String",
                global::System.Reflection.Assembly.Load("App_GlobalResources"));
            Regex regexp = new Regex("(?:\\[_)(?:.*)(?:_\\])", RegexOptions.Singleline);
            var text = manager.GetString(name, sCulture);
            var result = text;

            var shortCircuit = false;
            if (!string.IsNullOrEmpty(text))
            {
                var matches = regexp.Matches(text);
                while (matches.Count != 0 && shortCircuit == false)
                {
                    foreach (var match in matches)
                    {
                        var key = match.ToString().Replace("[_", "").Replace("_]", "");
                        var replacement = manager.GetString(key, sCulture) ?? match.ToString();
                        result = result.Replace(match.ToString(), replacement);
                        if (!replacement.Contains("[_"))
                        {
                            matches = regexp.Matches(result);
                        }
                        else
                        {
                            shortCircuit = true;
                            break;
                        }

                    }
                }
            }
            return result;
        }
    }  

Answer 1

我已经找到了解决方案。我只是为了使用CodeMethodInvokeExpression而更改了GetCodeExpression

public override CodeExpression GetCodeExpression(BoundPropertyEntry entry, object parsedData, ExpressionBuilderContext context)
        {
            var type = entry.DeclaringType;
            if (entry.DeclaringType != null)
            {
                return new CodeCastExpression(typeof(string), new CodeMethodInvokeExpression(new CodeTypeReferenceExpression(base.GetType()), "TranslateAndFill",
                    new CodePrimitiveExpression(entry.Expression.Trim())));
            }
            return new CodePrimitiveExpression((string)parsedData);

        }