private async void SearchBox_TextChangedAsync(object sender, EventArgs e)
{
var query = this.searchBox.Text;
var searchVersion = Interlocked.Increment(ref this.searchVersion);
await Task.Delay(TimeSpan.FromMilliseconds(500)).ConfigureAwait(true);
if (this.searchVersion != searchVersion)
{
return;
}
Predicate <SearchResult> predicate;
try
{
var term = new SearchGrammar().Parse(query ?? string.Empty);
predicate = this.searchCompiler.Compile(term);
}
catch
{
predicate = r => false;
}
if (this.searchVersion == searchVersion)
{
this.visiblePredicate = predicate;
this.UpdateListView();
}
}
public static SearchResult <T> FilterUsingIrony <T>(
this IQueryable <T> query,
string queryString,
params Expression <Func <T, string> >[] properties)
{
if (query == null)
{
throw new ArgumentNullException(nameof(query));
}
if (properties == null)
{
throw new ArgumentNullException(nameof(properties));
}
if (properties.Length == 0)
{
throw new ArgumentException("At least one property is expected", nameof(properties));
}
if (string.IsNullOrWhiteSpace(queryString))
{
return(new SearchResult <T>(query, Enumerable.Empty <string>()));
}
SearchGrammar searchGrammar = new SearchGrammar();
Parser parser = new Parser(searchGrammar);
ParseTree parseTree = parser.Parse(queryString);
if (parseTree.HasErrors() || parseTree.Root == null)
{
System.Diagnostics.Trace.WriteLine("Failed to parse search grammar '" + queryString);
string errors = string.Join(
"\r\n",
parseTree.ParserMessages
.Where(m => m.Level == Irony.ErrorLevel.Error)
.Select(m => m.Message));
throw new InvalidSearchException("The search term is invalid:\r\n" + errors);
}
var arg = Expression.Parameter(typeof(T), "p");
MemberExpression[] memberExpressions = new MemberExpression[properties.Length];
for (int i = 0; i < properties.Length; i++)
{
var propertyMemberExpression = properties[i].Body as MemberExpression;
if (propertyMemberExpression == null)
{
throw new ArgumentException(
"The " + i + "th property is invalid. Please provide property member expression like 'o => o.Name'",
nameof(properties));
}
string propertyString = propertyMemberExpression.ToString();
string name = propertyString.Substring(propertyString.IndexOf('.') + 1);
memberExpressions[i] = Expression.Property(arg, name);
}
var terms = new HashSet <string>();
var searchExpression = CreateChildExpression(parseTree.Root, memberExpressions, terms);
var searchPredicate = Expression.Lambda <Func <T, bool> >(searchExpression, arg);
return(new SearchResult <T>(query.Where(searchPredicate), terms));
}
