C# 大家帮帮小弟我啊！今天又遇到三个我不会的问题了！

Question

问题：1.要将datagridview1 中显示的数据导出txt文件中，要打开一个对话框，让用户可以选择txt文件
保存的路径。这要要怎么办？2.程序编译后有*.exe的图标要改成我们自已的图标，从哪改？3.配置文件是app.config，里面有连接数据库的参数，要编译后我要手动修改数据库的连接，能修改吗？

Answer 1

2.程序编译后有*.exe的图标要改成我们自已的图标，从哪改？ 
右击解决方案下面的那个属性 -》 应用程序 下面有个资源，资源里面有个图标的，可以选择的

Answer 2

   private void ExportExcel1()
        {
            string style = @"<style> .text { mso-number-format:\@; } </script> ";
            string Ftile = System.DateTime.Now.Year.ToString() + System.DateTime.Now.Month.ToString() + System.DateTime.Now.Day.ToString() + System.DateTime.Now.Hour.ToString();
            Response.Clear();
            Response.Buffer = true;
            Response.Charset = "GB2312";
            Response.AppendHeader("Content-Disposition", "attachment;filename=COM_" + Ftile + ".xls");
            // Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");//设置输出流为简体中文
            Response.ContentEncoding = System.Text.Encoding.UTF7;
            Response.ContentType = "application/ms-excel";//设置输出文件类型为excel文件。
            //       Response.Write("<meta http-equiv=Content-Type content=\"text/html; charset=GB2312\">");
            this.EnableViewState = false;
            System.Globalization.CultureInfo myCItrad = new System.Globalization.CultureInfo("ZH-CN", true);
            System.IO.StringWriter oStringWriter = new System.IO.StringWriter(myCItrad);
            System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);
            this.Gvexel.RenderControl(oHtmlTextWriter);//GVDY 是Gridview的ID名称
            Response.Write(style);
            Response.Write(oStringWriter.ToString());
            Response.End();        }

Answer 3

1.要将datagridview1 中显示的数据导出txt文件中，要打开一个对话框，让用户可以选择txt文件 
保存的路径。这要要怎么办？
FolderBrowserDialog可以选择路径的

Answer 4

1.用saveFileDialog1.ShowDialog();
2.VS上面可以设置
3.可以改

Answer 5

是WinForm的，不知道你是Web还是WinForm

Answer 6

项目--属性--应用程序--默认图标--选择个图标
public static bool DataTableToTxt(DataGridView gridview, string strFileName, char strSplit) 
      { 
          if (gridview == null||gridview.Rows.Count==0) 
              return false;           FileStream fileStream = new FileStream(strFileName, FileMode.OpenOrCreate); 
          StreamWriter streamWriter = new StreamWriter(fileStream, System.Text.Encoding.Unicode);           StringBuilder strBuilder = new StringBuilder();           try 
          { 
              for (int i = 0; i < gridview.Rows.Count; i++) 
              { 
                  strBuilder = new StringBuilder(); 
                  for (int j = 0; j < gridview.Columns.Count; j++) 
                  { 
                      strBuilder.Append(gridview.Rows[i].Cells[j].Value.ToString() + strSplit); 
                  } 
                  strBuilder.Remove(strBuilder.Length - 1, 1); 
                  streamWriter.WriteLine(strBuilder.ToString()); 
              } 
          } 
          catch(Exception ex) 
          { 
              string strErrorMessage = ex.Message; 
              return false; 
          } 
          finally 
          { 
              streamWriter.Close(); 
              fileStream.Close(); 
          }           return true; 
      }
public void SaveConfig(string configKey,string configValue) 
{ 
Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None); 
config.AppSettings.Settings.Clear(); 
config.AppSettings.Settings.Add(configKey, configValue); 
config.Save(); 
} 
public void SaveConfig(string configKey,string configValue) 
{ 
XmlDocument doc=new XmlDocument(); 
doc.Load(strFileName); 
XmlNodeList nodes=doc.GetElementsByTagName("add"); 
foreach (XmlNode node in nodes) 
{ 
XmlElement xe = (XmlElement)node; 
if (xe.GetAttribute("key") == configKey) 
{ 
xe.SetAttribute("value", configValue); 
} 
} 
doc.Save(strFileName); 
} public void SaveConfig(string configKey,string configValue) 
{ for (int i = 0; i < nodes.Count; i++) 
{ 
XmlAttribute att = nodes[i].Attributes["key"]; 
if (att.Value == "" + configKey + "")// if(att.Value == configKey) 
{ 
att = nodes[i].Attributes["value"]; 
att.Value = configValue; 
break; 
} 
} 
doc.Save(strFileName); } public static string GetConnectionStringsConfig(string connectionName) 
        { 
            try 
            { 
                string connectionString = 
                        ConfigurationManager.ConnectionStrings[connectionName].ConnectionString.ToString(); 
                Console.WriteLine(connectionString); 
                return connectionString; 
            } 
            catch 
            { 
                return ""; 
            } 
        }         public static void UpdateConnectionStringsConfig(string newName, string newConString, string newProviderName) 
        { 
            bool isModified = false;  
            if (ConfigurationManager.ConnectionStrings[newName] != null) 
            { 
                isModified = true; 
            } 
            ConnectionStringSettings mySettings = 
                new ConnectionStringSettings(newName, newConString, newProviderName); 
            Configuration config = 
                ConfigurationManager.OpenExeConfiguration(Application.ExecutablePath);//ConfigurationUserLevel.None 
            if (isModified)  
            { 
                config.ConnectionStrings.ConnectionStrings.Remove(newName); 
            } 
            config.ConnectionStrings.ConnectionStrings.Add(mySettings);      
            config.Save(ConfigurationSaveMode.Modified);      
            ConfigurationManager.RefreshSection("ConnectionStrings"); 
        }         public static string GetAppSettings(string SettingName) 
        { 
            return ConfigurationManager.AppSettings[SettingName].ToString();            
        } 
        public static void SetAppSettings(string AppKey, string AppValue) 
        { 
            XmlDocument doc = new XmlDocument(); 
            doc.Load(Application.ExecutablePath + ".config"); 
            XmlNode node = doc.SelectSingleNode(@"//add[@key='" + AppKey + "']"); 
            XmlElement ele = (XmlElement)node; 
            if (node != null) 
                ele.SetAttribute("value", AppValue); 
            else 
            { 
                XmlElement xElem2; 
                xElem2 = doc.CreateElement("add"); 
                xElem2.SetAttribute("key", AppKey); 
                xElem2.SetAttribute("value", AppValue); 
                node.AppendChild(xElem2); 
            } 
            doc.Save(Application.ExecutablePath + ".config");    
        }