When ASP. NET reads an Excel file, the following error occurs: The External table is not in the expected format.

Solution:
Open your Excel file in Notepad FileTo check whether it is garbled.
For HTML Code, Indicates that your Excel file format is not a standard Excel format, and the error "External table is not in the expected format" will be prompted;
If the code is garbled, I will not prompt this error during the test here. You can import it successfully.

In fact, the reason for this error is that your Excel is fromProgramAnd use
Response Method to directly output HTML code to excel
Actually, it can be solved. When exporting data, the Excel operation API is used to export the data in the standard format.
Bytes -----------------------------------------------------------------------------------------------------
This problem occurs when the Excel file output by response is modified and the file is uploaded for update,
"The External table is not in the expected format"
Solution:
1. Save the file as an Excel file in the standard xls Format (Response exports a webpage file)

2. directly operate Excel to generate data

Re-call import.