/// <summary>
/// 变量表达式
/// </summary>
/// <param name="parentExp"></param>
/// <param name="fieldName"></param>
/// <param name="isMethod"></param>
internal VariableExpression(VariableExpression parentExp, string fieldName, bool isMethod)
{
parentExp.NextExpression = this;
this.ParentExpression = parentExp;
this.VariableId = parentExp.VariableId;
this.FieldName = fieldName;
this.IsMethod = isMethod;
this.NeedCacheData = parentExp.NeedCacheData;
}
/// <summary>
/// 带变量字段的初始化
/// </summary>
/// <param name="ownerTemplate"></param>
/// <param name="varExp"></param>
internal VariableTag(Template ownerTemplate, VariableExpression varExp)
: base(ownerTemplate)
{
//注册添加属性时触发事件.用于设置自身的某些属性值
this.Attributes = new AttributeCollection(this);
this.Attributes.Adding += OnAddingAttribute;
this.VarExpression = varExp;
this.CallFunctions = new List<IExpression>();
}
/// <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 "from":
VariableExpression ve = item.Value as VariableExpression;
if (ve == null && this.OwnerDocument.DocumentConfig.CompatibleMode)
{
ve = ParserHelper.CreateVariableExpression(this.OwnerTemplate, item.Text, false);
}
this.From = ve;
break;
case "item":
this.Item = ParserHelper.CreateVariableIdentity(this.OwnerTemplate, item.Text);
break;
case "index":
this.Index = ParserHelper.CreateVariableIdentity(this.OwnerTemplate, item.Text);
break;
}
}
/// <summary>
/// 输出表达式的原字符串数据
/// </summary>
/// <returns></returns>
public override string ToString()
{
StringBuilder buffer = new StringBuilder();
buffer.Append(this.VariableId.ToString());
VariableExpression exp = this;
while (exp != null)
{
if (!string.IsNullOrEmpty(exp.FieldName))
{
buffer.Append(".");
buffer.Append(exp.FieldName);
if (exp.IsMethod)
{
buffer.Append("()");
}
}
exp = exp.NextExpression;
}
return(buffer.ToString());
}
/// <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;
}