Why are use ToString method ?

Question

Why are use  ToString method ?

 

 For example

cmd = new SqlCommand("Delete from Emp where Empid=" + DataGrid1.DataKeys[e.Item.ItemIndex].ToString(), con); 

 

 

but not use in VB

 

cmd = New SqlCommand("Update Emp Set Empname='" & name.Text & "',EmpAdd ='" & add.Text & "'where Empid=" & DataGrid1.DataKeys(e.Item.ItemIndex), con)