简单实现邮件模板功能

系统中经常有需要发送提醒邮件的需求，而且邮件类型和内容往往又不同，有些还需要跟业务字段做关联。这种情况下，就需要用到邮件模板功能，可以通过在模板中定义业务字段标记，通过模板引擎或自定义代码来实现这些字段的填充。

下面是一个自己写的简单的，字符串替换方式实现的邮件模板功能。代码如下：

public class DynamicTemplateBinder
{
    /// <summary>
    /// 邮件模板替换
    /// </summary>
    /// <param name="template"></param>
    /// <param name="model"></param>
    /// <returns></returns>
    public static string RanderTemplate(string template, object model)
    {
        string content = template;
        if (string.IsNullOrEmpty(template))
        {

        }

        // 获取对象的类型
        Type type = model.GetType();
        var properties = type.GetProperties();


        // 匹配$$FieldName$$
        Regex regex = new Regex(@"\$\$([a-zA-Z_\.][a-zA-Z0-9_\.]*)\$\$");
        var matches = regex.Matches(template);
        foreach (Match match in matches)
        {
            // Console.WriteLine(match.Groups[1].Value); // 输出不含大括号的字段名
            string propertyName = match.Groups[1].Value;
            var propertyInfo = type.GetProperty(propertyName);
            var propVal = string.Empty;
            if (propertyInfo != null)
            {
                var propertyValue = propertyInfo.GetValue(model, null);
                if (propertyValue != null)
                {
                    propVal = propertyValue.ToString();
                }
            }
            content = content.Replace(match.Value, propVal);
        }

        return content;
    }

    string RanderLoop(string template, object model)
    {
        // 获取对象的类型
        Type type = model.GetType();

        string content = template;
        Regex regex = new Regex(@"<<LoopStart[^>]*data=(.*?)>>(.*)<<LoopEnd>>");
        var matches = regex.Matches(template);
        foreach (Match match in matches)
        {
            string loopContent = string.Empty;
            var matchVal = match.Value;
            var loopPropertyName = match.Groups[1].Value;
            var loopPropertyInfo = type.GetProperty(loopPropertyName);
            if (loopPropertyInfo != null)
            {
                var loopProperyValue = loopPropertyInfo.GetValue(model, null);
                if (loopProperyValue != null && loopProperyValue is IEnumerable)
                {
                    string loopTemp = string.Empty;
                    foreach (var item in loopProperyValue as IEnumerable)
                    {
                        var itemType = item.GetType();
                        loopTemp = match.Groups[2].Value;
                        if (loopTemp != null)
                        {
                            string itemContent = loopTemp;
                            // 匹配$$FieldName$$
                            Regex fieldReg = new Regex(@"\$\$([a-zA-Z_\.][a-zA-Z0-9_\.]*)\$\$");
                            var fieldMatches = fieldReg.Matches(loopTemp);
                            foreach (Match fm in fieldMatches)
                            {
                                string propertyName = fm.Groups[1].Value;
                                var propertyInfo = itemType.GetProperty(propertyName);
                                var propVal = string.Empty;
                                if (propertyInfo != null)
                                {
                                    var propertyValue = propertyInfo.GetValue(item, null);
                                    if (propertyValue != null)
                                    {
                                        propVal = propertyValue.ToString();
                                    }
                                }
                                itemContent = itemContent.Replace(fm.Value, propVal);
                            }
                            loopContent += itemContent;
                        }
                    }
                }
            }
            content = template.Replace(matchVal, loopContent);
        }

        return content;
    }
}
　　

　　模板支持单层字段和简单列表绑定。