在通用里声明了如下语句，mrc As ADODB.Recordset总是出错，提示编译错误，用户定义类型未定义

Public actiontype As Integer '定义类型变量，区分动作种类
Dim txtSQL As String
Private txtSQL1 As String 'ExecuteSQL的SQL语句参数
Dim mrc As ADODB.Recordset
Private mrc1 As ADODB.Recordset '定义查询返回记录集
Dim MsgText As String
Dim inno As String '用来记录输入的图书编号
Dim i As Integer

多谢指点，现在已经解决此问题了。