private void AppendFirstLetterExpressions(StringBuilder sb, ViewPage page, SelectClauseDictionary expressions, string substringFunction)
{
foreach (DataField field in page.Fields)
if ((!(field.Hidden) && field.AllowQBE) && (field.Type == "String"))
{
string fieldName = field.AliasName;
if (String.IsNullOrEmpty(fieldName))
fieldName = field.Name;
sb.AppendFormat("distinct {1}({0},1,1) first_letter__\r\n", expressions[fieldName], substringFunction);
page.FirstLetters = fieldName;
page.RemoveFromFilter(fieldName);
break;
}
}