What causes "SR.Image_InInitialize" in dotnet/wpf?

Remove the redundant BeginInit call — only call it once before setting properties

dotnet/wpf · error · InvalidOperationException

SR.Image_InInitialize

Error message

SR.Image_InInitialize

What it means

BeginInit sets the _inInit flag; calling BeginInit again while an initialization block is already open means a previous BeginInit was never paired with EndInit. WPF throws InvalidOperationException with SR.Image_InInitialize to prevent nested initialization.

Solutions

Remove the redundant BeginInit call — only call it once before setting properties
Ensure EndInit is called in a finally block so a failed init resets state, and create a new instance for retries
Refactor helpers to accept an already-initializing object instead of calling BeginInit themselves

Example fix

// before
img.BeginInit();
Configure(img); // helper also calls img.BeginInit() -> throws
img.EndInit();
// after
img.BeginInit();
Configure(img); // helper only sets properties (UriSource, etc.)
img.EndInit();

Defensive patterns

Strategy: validation

Validate before calling

bool canEndInitSafely(BitmapImage img, ref bool begun) => begun == false; // call BeginInit only when no init block is open

Try / catch

try { img.BeginInit(); /* props */; img.EndInit(); }
catch (InvalidOperationException ex)
{
    // nested init: init block already open
    logger.LogError(ex, "Nested BeginInit on BitmapImage");
}

Prevention

Call BeginInit exactly once per init block, never inside helper methods that the caller also uses within the block
Ensure helpers only set properties, not BeginInit
Use try/finally so EndInit always runs after BeginInit, preventing leaked init state

When it happens

Trigger: Calling BeginInit() while IsInInit is true — i.e. a second BeginInit before the matching EndInit, typically from a helper method called inside an already-open BeginInit/EndInit block.

Common situations: A shared helper that calls BeginInit itself while the caller already called BeginInit; exception in the middle of init skipped EndInit, then retry logic calls BeginInit again; event handlers or async callbacks re-entering init code.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/c9b0ae85707e4b06. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/Imaging/BitmapInitialize.cs:24

namespace System.Windows.Media.Imaging
{
    #region BitmapInitialize
    /// <summary>
    /// Utility class providing support for ISupportInitialize
    /// </summary>
    internal class BitmapInitialize : ISupportInitialize
    {
        public BitmapInitialize()
        {
        }

        public void BeginInit()
        {
            if (IsInitAtLeastOnce)
                throw new InvalidOperationException(SR.Format(SR.Image_OnlyOneInit, null));

            if (IsInInit)
                throw new InvalidOperationException(SR.Format(SR.Image_InInitialize, null));

            _inInit = true;
        }

        public void EndInit()
        {
            if (!IsInInit)
                throw new InvalidOperationException(SR.Format(SR.Image_EndInitWithoutBeginInit, null));

            _inInit = false;
            _isInitialized = true;
        }

        public void SetPrologue()
        {
            if (!IsInInit)
            {
                throw new InvalidOperationException(SR.Format(SR.Image_SetPropertyOutsideBeginEndInit, null));

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