c# - Default combobox first item mixed with database results -

public static void fill_combo(string table, combobox cmb, string columns)     {         ds = new dataset();         try         {             conn.open();              da = new sqldataadapter($"select {columns} [{table}]", conn);              da.fill(ds, table);             cmb.datasource = ds.tables[table];             cmb.valuemember = ds.tables[table].columns[0].tostring();             cmb.displaymember = ds.tables[table].columns[1].tostring();              cmb.selecteditem = null;             cmb.text = "select...";          }         catch (exception ex)         {             messagebox.show(ex.message, "error");          }                 {             if (conn != null)             {                 conn.close();             }         }     } 

hey guys. code above i'm trying results database , bind them combobox, want first item random "select..." isn't in database. in advance.

option 1 - can insert datarow containing desired values datatable:

var connection = @"your connection string"; var command = "select column1, column2 table1"; var dt = new datatable(); using (var da = new sqldataadapter(command, connection))     da.fill(dt); var row = dt.newrow(); row["column1"] = dbnull.value; row["column2"] = "select item"; dt.rows.insertat(row, 0); this.combobox1.datasource = dt; this.combobox1.valuemember = "column1"; this.combobox1.displaymember = "column2"; 

option 2 - instead of adding null data datatable, can set dropdownstyle dropdownlist , set drawmode ownerdrawfixed , handle drawitem event , draw place holder when selected index -1:

private void combobox1_drawitem(object sender, drawitemeventargs e) {     var combo = sender combobox;     var text = "select item";     if (e.index > -1)         text = combo.getitemtext(combo.items[e.index]);     e.drawbackground();     textrenderer.drawtext(e.graphics, text, combo.font,         e.bounds, e.forecolor, textformatflags.left); } 

to show place holder, it's enough set combobox1.selectedindex = -1;