WarningInfo.WarningType property

Returns the type of the warning.

public WarningType WarningType { get; }


Shows how to set the property for finding the closest match for a missing font from the available font sources.

public void EnableFontSubstitution()
    // Open a document that contains text formatted with a font that does not exist in any of our font sources.
    Document doc = new Document(MyDir + "Missing font.docx");

    // Assign a callback for handling font substitution warnings.
    HandleDocumentSubstitutionWarnings substitutionWarningHandler = new HandleDocumentSubstitutionWarnings();
    doc.WarningCallback = substitutionWarningHandler;

    // Set a default font name and enable font substitution.
    FontSettings fontSettings = new FontSettings();
    fontSettings.SubstitutionSettings.DefaultFontSubstitution.DefaultFontName = "Arial";
    fontSettings.SubstitutionSettings.FontInfoSubstitution.Enabled = true;

    // Original font metrics should be used after font substitution.
    doc.LayoutOptions.KeepOriginalFontMetrics = true;

    // We will get a font substitution warning if we save a document with a missing font.
    doc.FontSettings = fontSettings;
    doc.Save(ArtifactsDir + "FontSettings.EnableFontSubstitution.pdf");

    using (IEnumerator<WarningInfo> warnings = substitutionWarningHandler.FontWarnings.GetEnumerator())
        while (warnings.MoveNext())

    // We can also verify warnings in the collection and clear them.
    Assert.AreEqual(WarningSource.Layout, substitutionWarningHandler.FontWarnings[0].Source);
        "Font '28 Days Later' has not been found. Using 'Calibri' font instead. Reason: alternative name from document.",


    Assert.AreEqual(0, substitutionWarningHandler.FontWarnings.Count);

public class HandleDocumentSubstitutionWarnings : IWarningCallback
    /// <summary>
    /// Called every time a warning occurs during loading/saving.
    /// </summary>
    public void Warning(WarningInfo info)
        if (info.WarningType == WarningType.FontSubstitution)

    public WarningInfoCollection FontWarnings = new WarningInfoCollection();

See Also