/// <summary>
/// 变量表达式
/// </summary>
/// <param name="variableId"></param>
/// <param name="fieldName"></param>
/// <param name="isMethod"></param>
/// <param name="needCacheData"></param>
internal VariableExpression(VariableIdentity variableId, string fieldName, bool isMethod, bool needCacheData)
{
this.VariableId = variableId;
this.FieldName = fieldName;
this.IsMethod = isMethod;
this.NeedCacheData = needCacheData;
}
/// <summary>
/// 添加标签属性时的触发函数.用于设置自身的某些属性值
/// </summary>
/// <param name="name"></param>
/// <param name="item"></param>
public override void OnAddingAttribute(string name, Attribute item)
{
switch (name)
{
case "index":
this.Index = ParserHelper.CreateVariableIdentity(this.OwnerTemplate, item.Text);
break;
}
}
/// <summary>
/// 克隆表达式
/// </summary>
/// <param name="ownerTemplate"></param>
/// <returns></returns>
public IExpression Clone(Template ownerTemplate)
{
VariableIdentity variableId = this.VariableId.Clone(ownerTemplate);
VariableExpression exp = new VariableExpression(variableId, this.FieldName, this.IsMethod, this.NeedCacheData);
if (this.NextExpression != null)
{
exp.NextExpression = (VariableExpression)(this.NextExpression.Clone(ownerTemplate));
exp.NextExpression.ParentExpression = exp;
}
return(exp);
}
/// <summary>
/// 构建变量标签元素
/// </summary>
/// <param name="ownerTemplate">宿主模板</param>
/// <param name="container">标签的容器</param>
/// <param name="match"></param>
internal static VariableTag CreateVariableTag(Template ownerTemplate, Tag container, Match match)
{
string prefix;
Variable variable = CreateVariable(ownerTemplate, match, out prefix);
VariableIdentity variableId = new VariableIdentity(ownerTemplate, variable, prefix);
//变量标签元素则需要缓存表达式的值
VariableExpression varExp = CreateVariableExpression(variableId, match, true);
VariableTag tag = new VariableTag(ownerTemplate, varExp);
//解析属性列表
ParseElementAttributes(tag, match);
container.AppendChild(tag);
return tag;
}
/// <summary>
/// 构建变量的字段列表
/// </summary>
/// <param name="variableId"></param>
/// <param name="match"></param>
/// <param name="needCacheData"></param>
/// <returns></returns>
internal static VariableExpression CreateVariableExpression(VariableIdentity variableId, Match match, bool needCacheData)
{
//解析变量字段列表
VariableExpression field = new VariableExpression(variableId, needCacheData);
CaptureCollection fields = match.Groups["field"].Captures;
CaptureCollection methods = match.Groups["method"].Captures;
VariableExpression item = field;
for (var i = 0; i < fields.Count; i++)
{
string fieldName = fields[i].Value;
VariableExpression exp = new VariableExpression(item, fieldName, !string.IsNullOrEmpty(methods[i].Value));
item = exp;
}
return field;
}
/// <summary>
/// 呈现本元素的数据
/// </summary>
/// <param name="writer"></param>
protected override void RenderTagData(System.IO.TextWriter writer)
{
decimal from = Utility.ConverToDecimal(this.From.Value.GetValue());
decimal step = this.Step == null ? 1 : Utility.ConverToDecimal(this.Step.Value.GetValue());
decimal to = Utility.ConverToDecimal(this.To.Value.GetValue());
decimal index = from;
LoopIndex li = new LoopIndex(index);
if (this.Index != null)
{
this.Index.Value = li;
}
if (step >= 0)
{
while (index <= to)
{
li.Value = index;
li.IsFirst = (index == from);
li.IsLast = (index == to);
if (this.Index != null)
{
this.Index.Variable.Reset();
}
base.RenderTagData(writer);
index += step;
}
}
else
{
while (index >= to)
{
li.Value = index;
li.IsFirst = (index == from);
li.IsLast = (index == to);
if (this.Index != null)
{
this.Index.Variable.Reset();
}
base.RenderTagData(writer);
index += step;
}
}
}
/// <summary>
/// 从变量表达式文本(如:name.age)中构建变量表达式
/// </summary>
/// <param name="ownerTemplate"></param>
/// <param name="expressionText"></param>
/// <param name="needCacheData"></param>
/// <returns></returns>
internal static VariableExpression CreateVariableExpression(Template ownerTemplate, string expressionText, bool needCacheData)
{
if (string.IsNullOrEmpty(expressionText)) return null;
Match match = ParserRegex.VarExpRegex.Match(expressionText);
if (match.Success)
{
string prefix;
Variable variable = CreateVariable(ownerTemplate, match, out prefix);
VariableIdentity variableId = new VariableIdentity(ownerTemplate, variable, prefix);
return CreateVariableExpression(variableId, match, needCacheData);
}
else
{
//非变量表达式
throw new ParserException(string.Format("变量表达式\"{0}\"的定义格式错误", expressionText));
}
}
/// <summary>
/// 变量表达式
/// </summary>
/// <param name="variableId"></param>
/// <param name="needCacheData"></param>
public VariableExpression(VariableIdentity variableId, bool needCacheData)
: this(variableId, null, false, needCacheData)
{
}