Pass a variable with vewstate on grid edit

I am trying to pass a variable with view state. I am setting the variable when the user clicks on the edit button
When I click on the edit button for the first time the variable is 0
What I am doing wrong?
public int test { get { if (ViewState["testing"] != null) return Convert.ToInt32(ViewState["testing"]); else return 0; } set { ViewState["testing"] = value; } } protected void grdTest_RowCommand(object sender, GridViewCommandEventArgs e) { if(e.CommandName == "EditRow") { test = Convert.ToInt32(e.CommandArgument); } }