c# 整理一

1.将DataTable中的某列转换成数组或者List

string[] arrRate = dtRate.AsEnumerable().Select(d => d.Field<string>("列名")).ToArray();
	
List<string> litRate = dtRate.AsEnumerable().Select(d => d.Field<string>("列名")).ToList();

2.使用事务　　

using (SqlConnection conn = new SqlConnection(DBObject.DBConnectionString))
{
conn.Open();
SqlTransaction tran = conn.BeginTransaction();
//此处省略将tran当做参数传入到SQLHelper函数文件
tran.commit
若异常
tran.rollback

 3.同一程序，禁止重复开启，在Program.cs中设置

  Mutex mutex = new System.Threading.Mutex(true, "OnlyRun");
            if (mutex.WaitOne(0, false))
            {
                Application.Run(new Form2());
            }
            else
            {
                MessageBox.Show("程序已经在运行！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                Application.Exit();
            }

 4.写日志方法

 static void WriteLog(string logmsg)
        {
            DateTime now = DateTime.Now;
            string rootdir = System.AppDomain.CurrentDomain.SetupInformation.ApplicationBase + @"DCFileLogs";
            DirectoryInfo di = new DirectoryInfo(rootdir);
            if (!System.IO.Directory.Exists(rootdir))
            {
                Directory.CreateDirectory(rootdir);
            }
            string path = string.Format(@"{0}{1}", rootdir, DateTime.Now.ToString("yyyy-MM-dd"));
            StreamWriter sw = new StreamWriter(path + ".txt", true);
            sw.WriteLine(now.ToString() + "	" + logmsg);
            sw.Close();
        } 

 5，通过数据库表名生成Model类

SELECT  a.name TableName,CONCAT('public class ', a.name, N'{', CHAR(9), ( SELECT CONCAT(CHAR(10), 'public ', CASE b.user_type_id
                                                                                              WHEN 61 THEN 'DateTime?'
                                                                                              WHEN 56 THEN 'int?'
                                                                                              WHEN 231 THEN 'string '
                                                                                              WHEN 167 THEN 'string'
                                                                                              WHEN 104 THEN 'bool?'
                                                                                              WHEN 106 THEN 'decimal'
                                                                                              ELSE 'UNKOWN'
                                                                                            END, ' ', b.name, '{get;set;}' + char(10))
                                                         FROM   sys.columns b
                                                         WHERE  b.object_id = a.object_id
                                                       FOR
                                                         XML PATH('')
                                                       ), CHAR(10), '}') TextSql
FROM    sys.tables a
WHERE   name IN( '表名')

SQL语句生成结果复制出来如下：

public class OABasicData{    
public int? FID{get;set;}

public string FName{get;set;}

public string  FDepart{get;set;}

public bool? IsEnable{get;set;}

public string FType{get;set;}

public string FMark{get;set;}

}

 6.asp.testbox限制只能输入大写字母

<asp:TextBox runat="server" ID="txtProjectName" Style="margin-left: 0px; text-transform:uppercase " Width="350px"
TabIndex="1"></asp:TextBox>

7.清空网页上asp:textbox值，（winform界面原理相同）

    public void ControlValueClear(System.Web.UI.Control page)
    {
        int count = page.Controls.Count;
        for (int i = 0; i < count; i++)
        {
            foreach (System.Web.UI.Control control in page.Controls[i].Controls)
            {
                if (control is TextBox)
                {
                    (control as TextBox).Text = string.Empty;

                }

            }
        }
    }

调用时，参数传入this,表示当前界面

 8.获取界面按钮post产生的数据，（做公司派车申请单，派车明细校验时使用到）

  private static string PostInput(System.Web.UI.Page page)
        {
            try
            {

                System.IO.Stream s = page.Request.InputStream;

                int count = 0;

                byte[] buffer = new byte[1024];

                StringBuilder builder = new StringBuilder();

                while ((count = s.Read(buffer, 0, 1024)) > 0)
                {

                    builder.Append(Encoding.UTF8.GetString(buffer, 0, count));

                }

                s.Flush();

                s.Close();

                s.Dispose();

                return builder.ToString();

            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

调用：

PostInput（this.page）

 C#继承中的override（重写）与new（覆盖）用法

  https://www.cnblogs.com/vsSure/p/7816639.html

委托与事件应用场景： https://www.cnblogs.com/guoqiang1/p/8138889.html