How to get and set public property value from UserCOntrol

I have a user control which has a public property. I set this property Initially when this User Control loads.
This User control is inside the grid. 
I have a submit button. When i click on submit button i want to retreive the property value of user control

//This is User controlpublic partial class MyUC : System.Web.UI.UserControl
{
private long _myvalue;
public long MyValue
{
get
{

return _myvalue;
}
set
{

_myvalue= value;
}
}

public void SetInitialValues(long v)
{
_myvalue = v;
}
} ...