/// <summary>
/// 根据指定表达式取表别名
/// </summary>
/// <param name="expression">表达式</param>
/// <remarks>
/// t=>t.Id
/// t.Id
/// </remarks>
public string GetTableAlias(Expression expression)
{
// p=>p.p
// p=>p.Id
// p=>p.t.Id
// p.Id
// p.t.Id
// p.t
// <>h__TransparentIdentifier0.p.Id
XFrameworkException.Check.NotNull(expression, "expression");
string key = TableAlias.GetTableAliasKey(expression);
return(this.GetTableAlias(key));
}
private static string GetTableAliasKey(Expression exp)
{
if (exp == null)
{
return(null);
}
Expression expression = exp.ReduceUnary();
//c
if (exp.CanEvaluate())
{
return(null);
}
// p
var parameter = expression as ParameterExpression;
if (parameter != null)
{
return(parameter.Name);
}
// a=>a.Id
var lambda = expression as LambdaExpression;
if (lambda != null)
{
expression = lambda.Body.ReduceUnary();
}
// a.Id
// t.a
// t.t.a
// t.a.Id
var member = expression as MemberExpression;
if (member == null)
{
return(TableAlias.GetTableAliasKey(expression));
}
if (member.Visitable())
{
return(TableAlias.GetTableAliasKey(member.Expression));
}
return(member.Member.Name);
}