加载图片到VBA用户窗体时出现Runtime Error 91错误求助

Hey there! Let's tackle that Runtime Error 91 you're hitting. This error usually pops up when you're trying to work with an object reference that's either Nothing or not set up the way you expect. Let's break down what's off in your code and how to fix it.

What's Causing the Error? #

Your problematic line:

Set img = ThisWorkbook.VBProject.VBComponents("UserForm10").Designer.Controls("Image3").Picture

has two critical issues:

• .Picture is a property, not an object you can assign with Set — trying to set an object variable to it will fail immediately.
• When loading an image at runtime, you don't need to dig into the VBProject designer. You can directly reference the form's image control using a form instance, which is the standard runtime approach.

Also, your check for the user canceling the file picker is slightly off: GetOpenFilename returns a Variant (a boolean False when canceled), not a string, so comparing it to "False" won't work correctly.

Corrected Code #

Here's the fixed version of your code that should run without errors:

Dim Pict As Variant ' Changed to Variant to handle boolean cancel value
Dim ImgFileFormat As String
Dim targetForm As UserForm10 ' Direct reference to your user form

ImgFileFormat = _
"Image Files (*.bmp;*.gif;*.tif;*.jpg),*.bmp;*.gif;*.tif;*.jpg" ' Fixed typo in file extensions

GetPict:
Pict = Application.GetOpenFilename(ImgFileFormat)
If Pict = False Then Exit Sub ' Correct comparison for the Variant return value

' Create an instance of your user form
Set targetForm = New UserForm10

' Load and configure the image directly in the control
With targetForm.Image3
    .Picture = LoadPicture(Pict)
    .PictureSizeMode = fmPictureSizeModeStretch
End With

' Show the form if you want to display the loaded image
targetForm.Show

Key Fixes Explained #

• Switched Pict to Variant: This lets you properly detect when the user cancels the file picker (since GetOpenFilename returns a boolean False in that case).
• Direct form instance: Instead of messing with the VBProject designer, we create an instance of UserForm10 and access its Image3 control directly — this is the standard, reliable way to interact with forms at runtime.
• Proper picture assignment: We set the .Picture property directly using LoadPicture(Pict) instead of trying to assign the property to an object variable first.
• Fixed file extension typo: Your original format string had *bmp instead of *.bmp, which ensures the file picker filters image files correctly.

Quick Additional Checks #

If you still run into issues, double-check:

• UserForm10 actually exists in your workbook's VBA project.
• Image3 is a valid Image control on UserForm10 (verify the name in the control's properties window).
• Your macro security settings allow access to the VBA project object model if you ever need to use VBProject in other code.

内容的提问来源于stack exchange，提问作者Adil