how can use category for post in to wordpress using c# -

hi program post wordpress using c# have problem. when post first on program 1 ok second time in have posted second post use 1 of first time category before have select. codes in category section same this:

    string[] category;     private void btnsend_click(object sender, eventargs e)     {          int index = listbox1.selectedindex;         if (index == -1)         {             messagebox.show("please select category");         }         else         {       } 

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