Access MDI form variable in another child form

[C# Programming]

Hi Friends

I am working with windows application..using C#.
I have and MDI form which have the following variables..

public String FranchisorName = "", FranchiseeName = "", ********Name = "", UserName = "";
public String strlblProcess, strlblBatch;
public String Flag = "";
public String QBFName = "";
public String ConnectionString;


and I wand access these values in another form i.e Child form which has the following code..

public frmMDIMain objMDIMain = new frmMDIMain();

String temp = objMDIMain.ConnectionString;


But I am not able to retirive the value of ConnectionString variable...

please help me out..
thanx in advance..