ComboBox FindString Contains - vb.net

Question

I have such entries in Winforms ComboBox:
Font 8 pt
Font 9 pt
Font 10 pt
Font 12 pt
Font 14 pt
Then I have search string " 9 ".
Is here native way to find index by search string without looping?
I try this:
Dim a As Integer = myComboBox.FindString(" 9 ", 0)
... but without good result.

Answer 1

First, no, there is no available method in the framework that searches for sub-string in combobox items and returns the index of the first item which contains the search parameter.
But even ComboBox.FindString uses a loop as you can see in the source.
So there is nothing bad in using one, you could write an extension method for this:
public static class ControlExtensions
{
public static int FindSubStringIndex(this ComboBox combo, string subString, StringComparison comparer = StringComparison.CurrentCulture)
{
// Sanity check parameters
if(combo == null) throw new ArgumentNullException("combo");
if (subString == null) {
return -1;
}
for (int index = 0; index < combo.Items.Count; index++)
{
object obj = combo.Items[index];
if(obj == null) continue;
string item = Convert.ToString(obj, CultureInfo.CurrentCulture);
if (string.IsNullOrWhiteSpace(item) && string.IsNullOrWhiteSpace(subString))
return index;
int indexInItem = item.IndexOf(subString, comparer);
if (indexInItem >= 0)
return index;
}
return -1;
}
}
Now you can use it in this way:
int index = combo.FindSubStringIndex("9");
Whoops, VB.NET:
Public Module ControlExtensions
<System.Runtime.CompilerServices.Extension> _
Public Function FindSubStringIndex(combo As ComboBox, subString As String, Optional comparer As StringComparison = StringComparison.CurrentCulture) As Integer
' Sanity check parameters
If combo Is Nothing Then
Throw New ArgumentNullException("combo")
End If
If subString Is Nothing Then
Return -1
End If
For index As Integer = 0 To combo.Items.Count - 1
Dim obj As Object = combo.Items(index)
If obj Is Nothing Then
Continue For
End If
Dim item As String = Convert.ToString(obj, CultureInfo.CurrentCulture)
If String.IsNullOrWhiteSpace(item) AndAlso String.IsNullOrWhiteSpace(subString) Then
Return index
End If
Dim indexInItem As Integer = item.IndexOf(subString, comparer)
If indexInItem >= 0 Then
Return index
End If
Next
Return -1
End Function
End Module