.NET学习（6） 使用WinForms进行GUI设计

 看了Modern C#系列课程6--使用WinForms进行GUI设计的笔记，主讲 俞晖

 

数据验证：

      在一个FORM上，有好几个TEXTBOX，这些TEXTBOX都要执行数据验证，验证输入的数据是否为整数。

      可以写一个验证函数，然后在每个TEXTBOX的事件中调用该函数进行验证。

      下面介绍的方法是在TEXTBOX的事件中加入这个验证函数。其实就是委托代理的使用。

       using System; using SWF = System.Windows.Forms; namespace Calculator { public class Validation { //被代理方法，验证数据 public static void IsInteger(object sender, System.ComponentModel.CancelEventArgs e) { SWF.TextBox txt; //TEXTBOX类型 txt = (SWF.TextBox) sender; try { int.Parse(txt.Text); } catch(FormatException) { SWF.MessageBox.Show(" Please enter a numeric value.", "Calculator"); e.Cancel = true; // cancel validation, returns focus } catch(OverflowException) { SWF.MessageBox.Show("Please enter an integer in the range " + int.MinValue + " ... " + int.MaxValue, "Calculator"); e.Cancel = true; // cancel validation, returns focus } catch(Exception ex) { SWF.MessageBox.Show("Unknown error: " + ex.Message, "Calculator"); e.Cancel = true; // cancel validation, returns focus } } }//class }//namespace

       通过下面的方法，为TEXTBOX增加/删除验证事件。TEXTBOX的CausesValidation属性必须为true，否则无效。

       //增加 this.txtNumber1.Validating += new System.ComponentModel.CancelEventHandler(Validation.IsInteger); //删除 this.txtNumber2.Validating -= new System.ComponentModel.CancelEventHandler(Validation.IsInteger);

 

 

       一般的，public static void main 都会在Form1主类中。为了以后使用方便，我们可以把它放到一个新建的App类中，设置这个新建的类为程序启动的入口，这样，可以在主界面生成之前做一些初始化的操作。

using System; using SWF = System.Windows.Forms; using ST = System.Threading; using T = System.Diagnostics.Trace; namespace BankCustomerApp { public class App { [STAThread] public static void Main() { try { SWF.Application.ThreadException += new ST.ThreadExceptionEventHandler(App.OnAppException); SWF.Application.ThreadExit += new System.EventHandler(App.OnAppExit); string logfile = System.AppDomain.CurrentDomain.BaseDirectory + "AppLog.txt"; System.IO.TextWriter log = new System.IO.StreamWriter(logfile); if (Globals.Trace) { System.Diagnostics.TextWriterTraceListener logger; logger = new System.Diagnostics.TextWriterTraceListener(log); System.Diagnostics.Trace.Listeners.Add(logger); System.Diagnostics.Trace.WriteLine("App starting: " + DateTime.Now); } SWF.Application.Run(new Form1()); } catch(Exception ex) { OnAppException(null, new ST.ThreadExceptionEventArgs(ex)); } } private static void OnAppException(object sender, ST.ThreadExceptionEventArgs e) { Exception ex; ex = e.Exception; SWF.MessageBox.Show("Halting due to error: " + ex.Message, "Bank Customer App", System.Windows.Forms.MessageBoxButtons.OK, System.Windows.Forms.MessageBoxIcon.Error); T.WriteLine("Generic Application Exception Handler:"); while (ex != null) { T.WriteLine(ex.GetType().FullName); T.Indent(); T.WriteLine("Msg: " + ex.Message); T.WriteLine("Trace: " + ex.StackTrace); T.Unindent(); T.Flush(); ex = ex.InnerException; }//while // halt app T.Close(); SWF.Application.Exit(); } private static void OnAppExit(object sender, System.EventArgs e) { T.Close(); // close trace file } }//class }//namespace

 

从一个窗体中调用另一个窗体：

using (FormInputID frm = new FormInputID())//创建被调用窗体 { DialogResult dr; //窗体返回值 int id; dr = frm.ShowDialog(); //显示被调用的窗体 if (dr == DialogResult.OK)//窗体返回值 { id = frm.CustomerID;//窗体控件的值 MessageBox.Show("Simulating search for customer " + id + "...", "Bank Customer App", MessageBoxButtons.OK, MessageBoxIcon.Information); } }

using的作用是被调用的窗体被关闭后就从内存中释放掉。就是using括起来的部分所用的内存，在程序执行到using之外后会被释放掉。

 

 

数据绑定：

1。取得数据

//BankCustomers.cs using System; using SC=System.Collections; using T=System.Diagnostics.Trace; namespace BankCustomerApp { public class BankCustomers { public static SC.ArrayList Read(string filename) { SC.ArrayList customers;//数据容器 customers = new SC.ArrayList(); T.WriteLineIf(Globals.Trace, "Reading customers from file '" + filename + "'."); T.Flush(); using (System.IO.StreamReader reader = new System.IO.StreamReader(filename)) { string fn, ln; decimal balance; BankCustomer bc; //从文件读取数据 fn = reader.ReadLine(); while (fn != null) { ln = reader.ReadLine(); balance = decimal.Parse( reader.ReadLine() ); //取得一组数据 bc = new BankCustomer(fn, ln, balance); //加入一组数据到容器 customers.Add(bc); //读下一条数据 fn = reader.ReadLine(); }//while }//using T.WriteLineIf(Globals.Trace, "Finished reading file!"); T.Flush(); return customers;//返回容器 } }//class }//namespace   

 2。设置一些变量

 //Globals.cs using System; using SC = System.Collections; using CFG = System.Configuration.ConfigurationSettings; namespace BankCustomerApp { public class Globals { public static readonly string AppHomeDir;//数据文件路径 public static SC.ArrayList Customers;//全局数据容器 public static readonly bool Trace; static Globals() { AppHomeDir = System.AppDomain.CurrentDomain.BaseDirectory; Customers = new SC.ArrayList(); try // to read trace setting { Trace = System.Convert.ToBoolean( CFG.AppSettings["Tracing"] ); } catch { Trace = false; } } }//class }//namespace

 3。数据类定义

 //BankCustomer.cs using System; namespace BankCustomerApp { public class BankCustomer : ICloneable { private string m_FirstName; private string m_LastName; private decimal m_Balance; public BankCustomer(string fn, string ln, decimal balance) { this.m_FirstName = fn; this.m_LastName = ln; this.m_Balance = balance; } public BankCustomer(string fn, string ln): this(fn, ln, 0.0M) { } public string FirstName { get { return this.m_FirstName; } } public string LastName { get { return this.m_LastName; } } public decimal Balance { get { return this.m_Balance; } } public string FormattedBalance { get { return this.GetFormattedBalance(); } } public string GetFormattedBalance() { return this.Balance.ToString("C", System.Globalization.NumberFormatInfo.CurrentInfo); } public override string ToString() { return this.LastName + ", " + this.FirstName; } }//class }//namespace

 4。数据绑定操作

 //在Form1.cs中进行数据绑定操作 private void Form1_Load(object sender, System.EventArgs e) { string filename; filename = Globals.AppHomeDir + "customers.txt"; //从数据文件读数据 Globals.Customers = BankCustomers.Read(filename); //数据绑定的操作方法 this.lstCustomers.DataSource = Globals.Customers; //不是数据绑定的操作方法 /* foreach (BankCustomer bc in Globals.Customers) this.lstCustomers.Items.Add(bc);//增加到listbox中 */ } private void lstCustomers_SelectedIndexChanged(object sender, System.EventArgs e) { BankCustomer bc; bc = (BankCustomer) this.lstCustomers.SelectedItem; T.WriteLineIf(Globals.Trace, "User selected '" + bc.ToString() + "."); T.Flush(); //绑定操作方法 this.txtFirstName.DataBindings.Clear(); this.txtLastName.DataBindings.Clear(); this.txtBalance.DataBindings.Clear(); this.txtFirstName.DataBindings.Add("Text", bc, "FirstName"); this.txtLastName.DataBindings.Add("Text", bc, "LastName"); this.txtBalance.DataBindings.Add("Text", bc, "FormattedBalance"); 不是绑定操作的方法 /* this.txtFirstName.Text = bc.FirstName; this.txtLastName.Text = bc.LastName; this.txtBalance.Text = bc.GetFormattedBalance(); */ }

 5。数据文件

//customers.txt kim lee 1000.00 zoya alvi 1000.00 jane doe 1000.00 joe freshman 12.50 pooja smith 122.01 rity upadhyaya 12000.00 stan nikolov 0.00