Hello friends,

in my app I have three comboboxes, which I use as filter for my model.

Qt Code: 
  1. QString str1 = combo1->currentText();
  2.     QString str2 = combo2->currentText();
  3.     QString str3 = combo3->currentText();
  4.  
  5.     QString filter1 = "field1='"+str1+"'";
  6.     QString filter2 = "field2='"+str2+"'";
  7.     QString filter3 = "field3= convert (datetime,'"+str3+"',120)";
  8.  
  9.  
  10.     if (str1!="" && str2 != "" && str3 != "")//111
  11.         model->setFilter( filter1 +" and "+ filter2 +" and "+filter3);
  12.     else if (str1=="" && str2 != "" && str3 != "")//011
  13.         model->setFilter( filter2 +" and "+filter3);
  14.     else if (str1=="" && str2 != "" && str3 == "")//010
  15.         model->setFilter( filter2 );
  16.     else if (str1=="" && str2 == "" && str3 != "")//001
  17.         model->setFilter( filter3 );
  18.     else if (str1!="" && str2 != "" && str3 == "")//110
  19.         model->setFilter( filter1 +" and "+ filter2 );
  20.     else if (str1!="" && str2 == "" && str3 != "")//101
  21.         model->setFilter( filter1 +" and "+ filter3 );
  22.     else if (str1!="" && str2 == "" && str3 == "")//100
  23.         model->setFilter( filter1 );
  24.     else
  25.     {
  26.         model->setTable(tableName);
  27.         model->select();
  28.     }
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As you can see I also give my combo a <""> for no filter, but I have always to check because a when I set a filter and when a filter has a "" it does not appear in my table.

So when I have only 3 filter I have to check 2^3 choises that is 8 or four filter with 2^4=16 that is much coding. Is there a elegant way to setting the filters???