public void GetListCollectionsNames() //Get all collections names from all DBs { List <string> DB_collections; //Set database using var collCursor = MongoDBData.GetDatabase(client).ListCollectionNames(); DB_collections = collCursor.ToList(); string[] ColNames_Array = DB_collections.ToArray(); comboBox_Collections.Items.AddRange(ColNames_Array); comboBox_Collections.Text = ColNames_Array[0]; }