string textToCheck =
    "Russian: Русский Текст. Greek: Κείμενο στην ελληνική γλώσσα. Japanese (unrepresentable): 日本";
// see the code example in ImGearPDEText.Add
ImGearPDEFont fontSerif = CreateFont("Times-Roman", "Type0", "Identity-H");
// Ensure that the text is fully representable by the font.
// Add a warning if not.
if (!fontSerif.IsTextRepresentable(textToCheck))
{
    System.Collections.Generic.IEnumerable<char> unrepresentableChars =
        fontSerif.FindUnrepresentableCharacters(textToCheck);
    string unrepresentableCharsString = String.Empty;
    foreach (char unrepresentableChar in unrepresentableChars)
    {
        if (unrepresentableCharsString != String.Empty)
        {
            unrepresentableCharsString += ",";
        }
        unrepresentableCharsString += unrepresentableChar;
    }
    MessageBox.Show(
        string.Format(
            "The selected font, {0}, does not support the following characters: [{1}]",
            fontSerif.GetAttributes().Name.String, unrepresentableCharsString));
}
	 
	
		Dim textToCheck As String = "Russian: Русский Текст. Greek: Κείμενο στην ελληνική γλώσσα. Japanese (unrepresentable): 日本"
' see the code example in ImGearPDEText.Add
Dim fontSerif As ImGearPDEFont = CreateFont("Times-Roman", "Type0", "Identity-H")
' Ensure that the text is fully representable by the font.
' Add a warning if not.
If Not fontSerif.IsTextRepresentable(textToCheck) Then
    Dim unrepresentableChars As System.Collections.Generic.IEnumerable(Of Char) = fontSerif.FindUnrepresentableCharacters(textToCheck)
    Dim unrepresentableCharsString As String = [String].Empty
    For Each unrepresentableChar As Char In unrepresentableChars
        If unrepresentableCharsString <> [String].Empty Then
            unrepresentableCharsString += ","
        End If
        unrepresentableCharsString += unrepresentableChar
    Next
    MessageBox.Show(String.Format("The selected font, {0}, does not support the following characters: [{1}]", fontSerif.GetAttributes().Name.[String], unrepresentableCharsString))