Either you can use the previouspage.findcontrol("gridview") method
or the best way you can find is use the Messenger class.
Use Messenger's Send and Register method to send the data and receive the data from one page to another.
Write below code in the file which you have to send object.
Messenger.Default.Send<object_datatype>(object,token);</object_datatype>
Write below code in the file which you have to receive object
Messenger.Default.Register<object_datatype>(this,token,Action);</object_datatype>
where object_datatype is the datatype of the object or value which you have to pass.
object is a object or value which you have to pass.
token is the specification or you can say tag. with this Messenger will find the Register method which have same token. and execute that only method.
for eg:
Messenger.Default.Send<bool>(true,"SendingStatemet");<br />
Messenger.Default.Register<bool>(this,"SendingStatement",(istrue)=><br />
{<br />
if(istrue)<br />
this.DialogResult=istrue;<br />
});</bool></bool>
Happy coding..