ACCESS，文件下载，DLL操作类，EXCEL导出方法备忘

/// <summary>
/// 这个类用于Access数据库的操作
/// </summary>
class AccessConnHelper
{
//数据库存放位置
public string FilePath { get; set; }

public  bool GetConnectionState()
{
OleDbConnection conn =GetNewConnection();
if (conn.State == ConnectionState.Open)
{
conn.Close();
return true;
}
else
return false;

}

/// <summary>
/// 获得新的数据库连接
/// </summary>
/// <returns>返回新连接</returns>
private  OleDbConnection GetNewConnection()
{
OleDbConnection oleDbConnection = new OleDbConnection();
oleDbConnection.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;data source=" + FilePath;

try
{
oleDbConnection.Open();
}
catch (Exception ex)
{
throw ex;
}
return oleDbConnection;
}

/// <summary>
/// 执行SQL语句，并返回一个OleDbDataReader对象。
/// </summary>
/// <param name="commandText">SQL语句</param>
/// <returns>OleDbDataReader对象</returns>
private  OleDbDataReader ExecuteReader(string commandText, OleDbParameter[] commandParm)
{
OleDbConnection oleDbConnection = GetNewConnection();
OleDbCommand oleDbCommand = new OleDbCommand(commandText, oleDbConnection);
PrepareCommand(oleDbCommand, commandParm);
try
{
OleDbDataReader dbDataReader = oleDbCommand.ExecuteReader(CommandBehavior.CloseConnection);
return dbDataReader;
}
catch (Exception e)
{
throw e;
}
}

private  void PrepareCommand(OleDbCommand oleDbCommand, OleDbParameter[] commandParms)
{
if (commandParms != null)
{
foreach (OleDbParameter parameter in commandParms)
{
if (parameter.Value == null)
{
parameter.Value = DBNull.Value;
}
oleDbCommand.Parameters.Add(parameter);
}
}
}

/// <summary>
/// 获取表中某一列有值得个数
/// </summary>
/// <param name="tableName">表名</param>
/// <param name="columnName">列名</param>
/// <returns></returns>
public string GetItemsNumber(string tableName, string columnName)
{
string sqlText = string.Format("SELECT COUNT(*) FROM [{0}] WHERE [{1}] is not null", tableName, columnName);
OleDbConnection oleDbConnection = GetNewConnection();
OleDbCommand oleDbCommand = new OleDbCommand(sqlText, oleDbConnection);
string result=oleDbCommand.ExecuteScalar().ToString();
oleDbConnection.Close();
return result;
}

/// <summary>
/// 从数据库中读取并返回所有URL列表。
/// </summary>
public List<string> GetAllList(string urlNumber,string tablename,string columen)
{
string sqlText = string.Format("SELECT TOP {0} [URL] FROM [{1}] where [{2}] is not null ORDER BY [{2}] DESC,[ID]", urlNumber, tablename,columen);
List<string> list = new List<string>();
OleDbDataReader oleDbDataReader =ExecuteReader(sqlText, null);
while (oleDbDataReader.Read())
{
list.Add(oleDbDataReader["URL"].ToString());
}
oleDbDataReader.Close();
return list;
}

/// <summary>
/// 返回数据库中所有的表项
/// </summary>
public DataTable GetAllTables()
{
return GetNewConnection().GetOleDbSchemaTable(OleDbSchemaGuid.Tables, new Object[] { null, null, null, "Table" });
}

/// <summary>
/// 返回所有列名
/// </summary>
public List<string> GetALLTitle(string tableName)
{
List<string> columnName = new List<string>();
DataTable dt = GetNewConnection().GetOleDbSchemaTable(OleDbSchemaGuid.Columns, new object[] { null, null,tableName, null });
foreach (DataRow dr in dt.Rows)
{
if (dr["COLUMN_NAME"].ToString().Substring(0, 1) == "_")
{
columnName.Add(dr["COLUMN_NAME"].ToString());
}
}
return columnName;
}
}

/// <summary>
/// 文件下载通用类
/// </summary>
public class LoadFile : System.Web.UI.Page
{
/// <summary>
/// 下载指定的路径的文件到本地
/// </summary>
/// <param name="filePath">文件在服务器的虚拟路径</param>
public void DownLoadFile(string filePath)
{
FileInfo file = new System.IO.FileInfo(Server.MapPath(filePath));//将虚拟路径转换成物理路径，获得文件的信息
if (File.Exists(Server.MapPath(filePath)))
{
string name = Path.GetFileName(Server.MapPath(filePath));
//存在文件
HttpContext.Current.Response.Clear();
HttpContext.Current.Response.Buffer = false;
//通知浏览器下载文件而不是打开
HttpContext.Current.Response.ContentType = "application/octet-stream";
HttpContext.Current.Response.Charset = "GB2312";//定义输出字符集
HttpContext.Current.Response.ContentEncoding = Encoding.Default;//输出内容的编码为默认编码
//下载的文件名
if (HttpContext.Current.Request.UserAgent.Contains("MSIE") || HttpContext.Current.Request.UserAgent.Contains("msie"))
{
// 如果客户端使用 Microsoft Internet Explorer，则需要编码
name = ToHexString(name);      // name =Server.UrlEncode(name); 功能等价
}

HttpContext.Current.Response.AppendHeader("content-disposition", "attachment;filename=" + name);
//文件的大小
HttpContext.Current.Response.AppendHeader("content-length", file.Length.ToString());
HttpContext.Current.Response.WriteFile(filePath);
HttpContext.Current.Response.End();//将当前所有缓冲区的输出内容发送到客户端，并停止页面的执行
}
}

/// <summary>
/// 为字符串中的非英文字符编码
/// </summary>
private string ToHexString(string s)
{
char[] chars = s.ToCharArray();
StringBuilder builder = new StringBuilder();
for (int index = 0; index < chars.Length; index++)
{
bool needToEncode = NeedToEncode(chars[index]);
if (needToEncode)
{
string encodedString = ToHexString(chars[index]);
builder.Append(encodedString);
}
else
{
builder.Append(chars[index]);
}
}

return builder.ToString();
}

/// <summary>
///指定一个字符是否应该被编码
/// </summary>
private bool NeedToEncode(char chr)
{
string reservedChars = "$-_.+!*'(),@=&";

if (chr > 127)
return true;
if (char.IsLetterOrDigit(chr) || reservedChars.IndexOf(chr) >= 0)
return false;

return true;
}

/// <summary>
/// 为非英文字符串编码
/// </summary>
private string ToHexString(char chr)
{
UTF8Encoding utf8 = new UTF8Encoding();
byte[] encodedBytes = utf8.GetBytes(chr.ToString());
StringBuilder builder = new StringBuilder();
for (int index = 0; index < encodedBytes.Length; index++)
{
builder.AppendFormat("%{0}", Convert.ToString(encodedBytes[index], 16));
}
return builder.ToString();
}
}

/// <summary>
/// 将DV导出EXCEL类
/// </summary>
public class ExcelCommand
{
public static void print(DataGridViewX dataGridView)
{
//导出到execl
//没有数据的话就不往下执行
if (dataGridView.Rows.Count == 0)
return;
//实例化一个Excel.Application对象
Microsoft.Office.Interop.Excel.Application Excel = new Microsoft.Office.Interop.Excel.Application();

//让后台执行设置为不可见，为true的话会看到打开一个Excel，然后数据在往里写
Excel.Visible = false;

//新增加一个工作簿，Workbook是直接保存，不会弹出保存对话框，加上Application会弹出保存对话框，值为false会报错
Excel.Application.Workbooks.Add(true);

//生成Excel中列头名称
for (int i = 0; i < dataGridView.Columns.Count; i++)
{
Excel.Cells[1, i + 1] = dataGridView.Columns[i].HeaderText;
}
//把DataGridView当前页的数据保存在Excel中
for (int i = 0; i < dataGridView.Rows.Count - 1; i++)
{
for (int j = 0; j < dataGridView.Columns.Count; j++)
{
Excel.Cells[i + 2, j + 1] = dataGridView[j, i].Value.ToString();
}
}

//设置禁止弹出保存和覆盖的询问提示框
Excel.DisplayAlerts = false;
Excel.AlertBeforeOverwriting = false;

//保存工作簿
Excel.Application.Workbooks.Add(true).Save();
//保存excel文件
Excel.Save();

//确保Excel进程关闭
Excel.Quit();
Excel = null;

}

public static void KillProcess()
{
//获得进程对象，以用来操作
System.Diagnostics.Process myproc = new System.Diagnostics.Process();
//得到所有打开的进程
try
{
//获得需要杀死的进程名
foreach (Process thisproc in Process.GetProcessesByName("EXCEL"))
{
//立即杀死进程
thisproc.Kill();
}
}
catch (Exception Exc)
{
throw new Exception("", Exc);
}
}
}

/// <summary>
/// 调用cmd程序
/// </summary>
/// <param name="commandText">cmd指令</param>
/// <returns>结果</returns>
private string ExeCommand(string commandText)
{
using (Process p = new Process())
{
p.StartInfo.FileName = "cmd.exe";
//将此属性设置为 false 能够重定向输入流、输出流和错误流。
p.StartInfo.Arguments ="/c "+ commandText;
p.StartInfo.UseShellExecute = false;
p.StartInfo.RedirectStandardInput = true;
p.StartInfo.RedirectStandardOutput = true;
p.StartInfo.RedirectStandardError = true;
p.StartInfo.CreateNoWindow = true;
p.Start();
p.Close();
return null;
}
}