d2phap/ImageGlass · error · ArgumentException

Frame index '{frameIndexStr}' is not a valid integer. -----

Error message

Frame index '{frameIndexStr}' is not a valid integer.

----------
👉🏼 Method: IG_ViewFrame

What it means

Thrown by the string overload of IG_ViewFrame when int.TryParse(frameIndexStr) fails. The method parses a frame index for a multi-frame photo (GIF/WEBP animation) before delegating to the int overload. Out-of-range indices are looped safely downstream; only a non-integer string throws here.

Source

Thrown at source/ImageGlass.Lib/Common/ServiceProviders/AppAPIs/AppAPIProvider.cs:1095


    /// <summary>
    /// Views the last photo in the list.
    /// </summary>
    public void IG_GoToLast()
    {
        IG_ViewByIndex((int)Core.Photos.Count - 1);
    }


    /// <summary>
    /// View a frame of the current photo.
    /// </summary>
    public void IG_ViewFrame(string? frameIndexStr)
    {
        if (!int.TryParse(frameIndexStr, out var frameIndex))
        {
            throw new ArgumentException($"""
                Frame index '{frameIndexStr}' is not a valid integer.

                ----------
                👉🏼 Method: {nameof(IG_ViewFrame)}
                """,
                nameof(frameIndexStr));
        }

        IG_ViewFrame(frameIndex);
    }


    /// <summary>
    /// View a frame of the current photo.
    /// If the frame index is out of range, it will be looped.
    /// </summary>
    public static void IG_ViewFrame(int frameIndex)
    {

View on GitHub (pinned to 4a3c4fecef)

Solutions

Pass a plain integer string for the frame index ('0', '1', '2', ...).
Validate with int.TryParse upstream and call the int overload directly.
Trim and reject empty input before invoking.

Example fix

// before
api.IG_ViewFrame(userInput);

// after
if (int.TryParse(userInput?.Trim(), out var frame))
{
    api.IG_ViewFrame(frame);
}

Defensive patterns

Strategy: validation

Validate before calling

if (!int.TryParse(frameIndexStr?.Trim(), out var frame))
    throw new ArgumentException("Frame index must be an integer.");
api.IG_ViewFrame(frame);

Type guard

static bool IsValidFrameIndex(string? s) => int.TryParse(s?.Trim(), out _);

Try / catch

try { api.IG_ViewFrame(frameIndexStr); }
catch (ArgumentException ex) when (ex.ParamName == nameof(frameIndexStr))
{ /* reject the input */ }

Prevention

Pass plain integer strings for the frame index.
Validate upstream with int.TryParse and call the int overload.
Trim user input before parsing.

When it happens

Trigger: Calling IG_ViewFrame(string) with a non-numeric frame index: 'first', '2.5', '' , or a string with whitespace.

Common situations: Hotkey bound to a frame navigation command with a non-numeric argument; script passing a label instead of an index; current photo is single-frame (the int overload returns early, but the string parse happens first).

Related errors

AI-assisted analysis of d2phap/ImageGlass@4a3c4fecef (2026-08-13). Data as JSON: /api/errors/2030aef706f14042. Report an issue: GitHub.