Home Backend Development C++ How Can I Determine a File's MIME Type Using File Signatures in .NET?

How Can I Determine a File's MIME Type Using File Signatures in .NET?

Jan 31, 2025 pm 02:56 PM

How Can I Determine a File's MIME Type Using File Signatures in .NET?

The signature of the file in the .NET determined the file MIME type

The Mime type of accurately identifying files is essential for the correct processing and operation. When the file extension is lacking or incorrect, the file signature must be relying on the file type to accurately determine the file type. This article discusses how to achieve this function in the .NET.

solution using urlmon.dll

The solution provided using the URLmon.dll library to extract the MIME type based on the file signature. This method can be implemented through the following steps:

Introduce the necessary assembly set:
  1. Define the FindMimefromdata function:
    using System.Runtime.InteropServices;
    Copy after login
  2. <建> Create a function that searches the MIME type from the file:

    [DllImport(@"urlmon.dll", CharSet = CharSet.Auto)]
    private static extern uint FindMimeFromData(
        uint pBC,
        [MarshalAs(UnmanagedType.LPStr)] string pwzUrl,
        [MarshalAs(UnmanagedType.LPArray)] byte[] pBuffer,
        uint cbSize,
        [MarshalAs(UnmanagedType.LPStr)] string pwzMimeProposed,
        uint dwMimeFlags,
        out uint ppwzMimeOut,
        uint dwReserverd
    );
    Copy after login
  3. Use the getMimefromFile function to obtain the MIME type:

    public static string GetMimeFromFile(string filename)
    {
        // 为简洁起见,省略文件验证
        byte[] buffer = new byte[256];
        //...
    
        try
        {
            uint mimetype;
            FindMimeFromData(0, null, buffer, 256, null, 0, out mimetype, 0);
            IntPtr mimeTypePtr = new IntPtr(mimetype);
            string mime = Marshal.PtrToStringUni(mimeTypePtr);
            Marshal.FreeCoTaskMem(mimeTypePtr);
            return mime;
        }
        catch (Exception e)
        {
            return "unknown/unknown";
        }
    }
    Copy after login
  4. Please note that some code is omitted in the above code fragments, such as the first 256 bytes of reading the file to the array. Complete implementation requires the necessary error processing and file reading logic. In addition, the use of method may depend on the operating system, and compatibility problems may be existed in different environments. More stable solutions may need to consider using other .NET libraries or implement file signature analysis by themselves.

The above is the detailed content of How Can I Determine a File's MIME Type Using File Signatures in .NET?. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
3 weeks ago By 尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. Best Graphic Settings
3 weeks ago By 尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. How to Fix Audio if You Can't Hear Anyone
3 weeks ago By 尊渡假赌尊渡假赌尊渡假赌
WWE 2K25: How To Unlock Everything In MyRise
4 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

C language data structure: data representation and operation of trees and graphs C language data structure: data representation and operation of trees and graphs Apr 04, 2025 am 11:18 AM

C language data structure: The data representation of the tree and graph is a hierarchical data structure consisting of nodes. Each node contains a data element and a pointer to its child nodes. The binary tree is a special type of tree. Each node has at most two child nodes. The data represents structTreeNode{intdata;structTreeNode*left;structTreeNode*right;}; Operation creates a tree traversal tree (predecision, in-order, and later order) search tree insertion node deletes node graph is a collection of data structures, where elements are vertices, and they can be connected together through edges with right or unrighted data representing neighbors.

How do I use rvalue references effectively in C  ? How do I use rvalue references effectively in C ? Mar 18, 2025 pm 03:29 PM

Article discusses effective use of rvalue references in C for move semantics, perfect forwarding, and resource management, highlighting best practices and performance improvements.(159 characters)

The truth behind the C language file operation problem The truth behind the C language file operation problem Apr 04, 2025 am 11:24 AM

The truth about file operation problems: file opening failed: insufficient permissions, wrong paths, and file occupied. Data writing failed: the buffer is full, the file is not writable, and the disk space is insufficient. Other FAQs: slow file traversal, incorrect text file encoding, and binary file reading errors.

How do I use ranges in C  20 for more expressive data manipulation? How do I use ranges in C 20 for more expressive data manipulation? Mar 17, 2025 pm 12:58 PM

C 20 ranges enhance data manipulation with expressiveness, composability, and efficiency. They simplify complex transformations and integrate into existing codebases for better performance and maintainability.

How does dynamic dispatch work in C   and how does it affect performance? How does dynamic dispatch work in C and how does it affect performance? Mar 17, 2025 pm 01:08 PM

The article discusses dynamic dispatch in C , its performance costs, and optimization strategies. It highlights scenarios where dynamic dispatch impacts performance and compares it with static dispatch, emphasizing trade-offs between performance and

How do I use move semantics in C   to improve performance? How do I use move semantics in C to improve performance? Mar 18, 2025 pm 03:27 PM

The article discusses using move semantics in C to enhance performance by avoiding unnecessary copying. It covers implementing move constructors and assignment operators, using std::move, and identifies key scenarios and pitfalls for effective appl

What are the basic requirements for c language functions What are the basic requirements for c language functions Apr 03, 2025 pm 10:06 PM

C language functions are the basis for code modularization and program building. They consist of declarations (function headers) and definitions (function bodies). C language uses values ​​to pass parameters by default, but external variables can also be modified using address pass. Functions can have or have no return value, and the return value type must be consistent with the declaration. Function naming should be clear and easy to understand, using camel or underscore nomenclature. Follow the single responsibility principle and keep the function simplicity to improve maintainability and readability.

What is auto type deduction? What are its benefits and limitations? What is auto type deduction? What are its benefits and limitations? Mar 26, 2025 pm 11:23 PM

The article discusses auto type deduction in programming, detailing its benefits like reduced code verbosity and improved maintainability, and its limitations such as potential confusion and debugging challenges.

See all articles