c#
几秒 读完 (大约 106 个字)

C#把文件转成二进制数组

本文实现了在C#中，知道文件的路径后，读取该文件内容，并转换为byte数组返回的方法。

源代码

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class FileHelper{
    /// <summary>
    /// 
    /// </summary>
    /// <param name="fileName"></param>
    /// <returns></returns>
    public static byte[] ToBytes(string fileName)
    {
        using (var stream = File.Open(fileName, FileMode.Open))
        {
            var buffer = new byte[1024];
            using (var ms = new MemoryStream())
            {
                int read;
                while ((read = stream.Read(buffer, 0, buffer.Length)) > 0)
                {
                    ms.Write(buffer, 0, read);
                }
                return ms.ToArray();
            }
        }
    }
}

调用示例：

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var fileName="D://测试文件.txt";
var fileContent = FileHelper.ToBytes(fileName);

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扩展方法
几秒 读完 (大约 106 个字)

扩展ObservableCollection<T>，增加AddRange<T>()方法

扩展ObservableCollection，实现添加集合的扩展，当集合中新增、修改或者删除项目时，或者集合被刷新时，触发通知(通过实现接口INotifyCollectionChanged)。

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using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;

namespace ReflectionIT.WPF {

    public static class Extensions {

        public static void AddRange<T>(this ObservableCollection<T> oc, IEnumerable<T> collection) {
            if (collection == null) {
                throw new ArgumentNullException("collection");
            }
            foreach (var item in collection)
            {
                oc.Add(item);
            }

            
        }
    }
}
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扩展方法
2 分钟 读完 (大约 312 个字)

C#语言中的Encrypt和Decrypt

使用RSACryptoServiceProvider加密和解密一个字符串。

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;

namespace Extensions
{
    public static class Extensions
    {
        /// <summary>
        /// Encryptes a string using the supplied key. Encoding is done using RSA encryption.
        /// </summary>
        /// <param name="stringToEncrypt">String that must be encrypted.</param>
        /// <param name="key">Encryptionkey.</param>
        /// <returns>A string representing a byte array separated by a minus sign.</returns>
        /// <exception cref="ArgumentException">Occurs when stringToEncrypt or key is null or empty.</exception>
        public static string Encrypt(this string stringToEncrypt, string key)
        {
            if (string.IsNullOrEmpty(stringToEncrypt))
            {
                throw new ArgumentException("An empty string value cannot be encrypted.");
            }

            if (string.IsNullOrEmpty(key))
            {
                throw new ArgumentException("Cannot encrypt using an empty key. Please supply an encryption key.");
            }

            CspParameters cspp = new CspParameters();
            cspp.KeyContainerName = key;

            RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(cspp);
            rsa.PersistKeyInCsp = true;

            byte[] bytes = rsa.Encrypt(System.Text.UTF8Encoding.UTF8.GetBytes(stringToEncrypt), true);

            return BitConverter.ToString(bytes);
        }

        /// <summary>
        /// Decryptes a string using the supplied key. Decoding is done using RSA encryption.
        /// </summary>
        /// <param name="stringToDecrypt">String that must be decrypted.</param>
        /// <param name="key">Decryptionkey.</param>
        /// <returns>The decrypted string or null if decryption failed.</returns>
        /// <exception cref="ArgumentException">Occurs when stringToDecrypt or key is null or empty.</exception>
        public static string Decrypt(this string stringToDecrypt, string key)
        {
            string result = null;

            if (string.IsNullOrEmpty(stringToDecrypt))
            {
                throw new ArgumentException("An empty string value cannot be encrypted.");
            }

            if (string.IsNullOrEmpty(key))
            {
                throw new ArgumentException("Cannot decrypt using an empty key. Please supply a decryption key.");
            }

            try
            {
                CspParameters cspp = new CspParameters();
                cspp.KeyContainerName = key;

                RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(cspp);
                rsa.PersistKeyInCsp = true;

                string[] decryptArray = stringToDecrypt.Split(new string[] { "-" }, StringSplitOptions.None);
                byte[] decryptByteArray = Array.ConvertAll<string, byte>(decryptArray, (s => Convert.ToByte(byte.Parse(s, System.Globalization.NumberStyles.HexNumber))));


                byte[] bytes = rsa.Decrypt(decryptByteArray, true);

                result = System.Text.UTF8Encoding.UTF8.GetString(bytes);

            }
            finally 
            {
                // no need for further processing
            }

            return result;
        }

        
    }
}
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扩展方法
1 分钟 读完 (大约 172 个字)

C#语言判断两个数据表的内容是否相同

判断两个数据表的内容是否相同

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public static bool EqualsByContent(this DataTable thisDataTable, DataTable otherDataTable)
{
    // Compare row count.
    if (thisDataTable.Rows.Count != otherDataTable.Rows.Count)
    {
        return false;
    }

    // Compare column count.
    if (thisDataTable.Columns.Count != otherDataTable.Columns.Count)
    {
        return false;
    }

    // Compare data in each cell of each row.
    for (int i = 0; i < thisDataTable.Rows.Count; i++)
    {
        for (int j = 0; j < thisDataTable.Columns.Count; j++)
        {
            if (!thisDataTable.Rows[i][j].Equals(otherDataTable.Rows[i][j]))
            {
                return false;
            }
        }
    }

    // The two DataTables contain the same data.
    return true;
}
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扩展方法
1 分钟 读完 (大约 182 个字)

将DataReader转换为CSV

导出DataReader为CSV (List).

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public static List<string> ToCSV(this IDataReader dataReader, bool includeHeaderAsFirstRow, string separator)
{
    List<string> csvRows = new List<string>();
    StringBuilder sb = null;

    if (includeHeaderAsFirstRow)
    {
        sb = new StringBuilder();
        for (int index = 0; index < dataReader.FieldCount; index++)
        {
            if (dataReader.GetName(index) != null)
                sb.Append(dataReader.GetName(index));

            if (index < dataReader.FieldCount - 1)
                sb.Append(separator);
        }
        csvRows.Add(sb.ToString());
    }

    while (dataReader.Read())
    {
        sb = new StringBuilder();
        for (int index = 0; index < dataReader.FieldCount - 1; index++)
        {
            if (!dataReader.IsDBNull(index))
            {
                string value = dataReader.GetValue(index).ToString();
                if (dataReader.GetFieldType(index) == typeof(String))
                {
                    //If double quotes are used in value, ensure each are replaced but 2.
                    if (value.IndexOf("\"") >= 0)
                        value = value.Replace("\"", "\"\"");

                    //If separtor are is in value, ensure it is put in double quotes.
                    if (value.IndexOf(separator) >= 0)
                        value = "\"" + value + "\"";
                }
                sb.Append(value);
            }

            if (index < dataReader.FieldCount - 1)
                sb.Append(separator);
        }

        if (!dataReader.IsDBNull(dataReader.FieldCount - 1))
            sb.Append(dataReader.GetValue(dataReader.FieldCount - 1).ToString().Replace(separator, " "));

        csvRows.Add(sb.ToString());
    }
    dataReader.Close();
    sb = null;
    return csvRows;
}
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扩展方法
几秒 读完 (大约 111 个字)

C#扩展格式化方法

C#扩展格式化方法

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/// <summary>
/// Formats the string according to the specified mask
/// </summary>
/// <param name="input">The input string.</param>
/// <param name="mask">The mask for formatting. Like "A##-##-T-###Z"</param>
/// <returns>The formatted string</returns>
public static string FormatWithMask(this string input, string mask)
{
    if (input.IsNullOrEmpty()) return input;
    var output = string.Empty;
    var index = 0;
    foreach (var m in mask)
    {
        if (m == '#')
        {
            if(index < input.Length)
            {
                output += input[index];
                index++;
            }
        }
        else
            output += m;
    }
    return output;
}
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扩展方法
几秒 读完 (大约 58 个字)

C#语言中通过列名获取该列在excel中的索引

通过列名获取该列在excel中的索引

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public static int ExcelColumnIndex(this string columnName)
{
	int number = 0;
	int pow = 1;

	for (int i = columnName.Length - 1; i >= 0; i--)
	{
		number += (columnName[i] - 'A' + 1) * pow;
		pow *= 26;
	}

	return number;
}
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扩展方法
几秒 读完 (大约 107 个字)

C#扩展foreach，可以传入action

C#扩展foreach，可以传入action

源代码：

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public static IEnumerable<T> ForEach<T>(this IEnumerable<T> array, Action<T> act)
{
    foreach (var i in array)
        act(i);
    return array;
}

public static IEnumerable<T> ForEach<T>(this IEnumerable arr, Action<T> act)
{
    return arr.Cast<T>().ForEach<T>(act);
}

public static IEnumerable<RT> ForEach<T, RT>(this IEnumerable<T> array, Func<T, RT> func)
{
    var list = new List<RT>();
    foreach (var i in array)
    {
        var obj = func(i);
        if (obj != null)
            list.Add(obj);
    }
    return list;
}
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扩展方法
1 分钟 读完 (大约 185 个字)

InsertSorted

Insert an item to a sorted List

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static class Extensions {

    public static int InsertSorted<T>(this IList<T> source, T value) where T : IComparable<T> {
        if (source is null) {
            throw new ArgumentNullException(nameof(source));
        }
        for (int i = 0; i < source.Count; i++) {
            if (value.CompareTo(source[i]) < 0) {
                source.Insert(i, value);
                return i;
            }
        }
        source.Add(value);
        return source.Count - 1;
    }

    public static int InsertSorted<T>(this IList<T> source, T value, IComparer<T> comparison) {
        if (source is null) {
            throw new ArgumentNullException(nameof(source));
        }
        for (int i = 0; i < source.Count; i++) {
            if (comparison.Compare(value, source[i]) < 0) {
                source.Insert(i, value);
                return i;
            }
        }
        source.Add(value);
        return source.Count - 1;
    }

    public static int InsertSorted<T>(this IList<T> source, T value, Comparison<T> comparison)  {
        if (source is null) {
            throw new ArgumentNullException(nameof(source));
        }
        for (int i = 0; i < source.Count; i++) {
            if (comparison(value, source[i]) < 0) {
                source.Insert(i, value);
                return i;
            }
        }
        source.Add(value);
        return source.Count - 1;
    }
}
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扩展方法
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IsValidUrl

Returns true when a string is a valid url

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public static class MyExtensionMethods {
        public static bool IsValidUrl(this string text) {
            Regex rx = new Regex(@"http(s)?://([\w-]+\.)+[\w-]+(/[\w- ./?%&=]*)?");
            return rx.IsMatch(text);
        }
    }
}
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