得到一个工作流当前结点里面的可用选项

string s = txtGuid.Text.Trim();
if(s.Length>0)
{
Guid instanceId = new Guid(s);
StateMachineWorkflowInstance stateInstance = new StateMachineWorkflowInstance(Application[MyWorkHelpr.WorkflowRuntimeName] as WorkflowRuntime, instanceId);
using(DataTable dt = new DataTable())
{
dt.Columns.Add("NID",typeof(string));
dt.Columns.Add("NTEXT",typeof(string));
dt.Rows.Add("-1","==请选择==");
int i=0;
foreach(Activity act in stateInstance.CurrentState.EnabledActivities)
{
if (act is EventDrivenActivity )
{
EventDrivenActivity edact = (EventDrivenActivity)act;
if (edact.EnabledActivities.Count >0 && edact.EnabledActivities[0] is HandleExternalEventActivity)
{
dt.Rows.Add(edact.Name, act.Description);
}
}
i++;
}
DropDownList1.DataValueField = "NID";
DropDownList1.DataTextField = "NTEXT";
DropDownList1.DataSource = dt;
DropDownList1.DataBind();