.NET enabled Microsoft's marketing people to emphasise the "Network"-ing aspect of its technologies, and was also a reaction to the marketing blitz by Sun Microsystems in the late 1990s whose theme was "The network is the computer". The term "Dot-Com" was synonymous with the Internet that time, and "Dot-NET" was a play on that term.或多或少我都同認的，90年代正值Internet發展年代，叫".NET"，有點意識流，令人感覺.NET Framework不單是Offline本機的技術，而是關聯到Internet。
try
{
object obj = "abcd";
double d = Convert.ToDouble(obj);
}
catch (Exception ex)
{
System.Diagnostics.Debug.Print(ex.Message); //Output : 輸入字串格式不正確。
}
System.Threading.Thread.CurrentThread.CurrentCulture = System.Globalization.CultureInfo.CreateSpecificCulture("en-US");
System.Threading.Thread.CurrentThread.CurrentUICulture = new System.Globalization.CultureInfo("en-US");
try
{
object obj = "abcd";
double d = Convert.ToDouble(obj);
}
catch (Exception ex)
{
System.Diagnostics.Debug.Print(ex.Message); //Output : Input string was not in a correct format.
}
但繁中卻不可能轉成簡中，其他語系如日文更不可能，因為英文是.NET Framework的母系語言。
Dim s As String() = New String(3) {"1", "2", "3", "a"}
Dim i As Integer
For Each _s As String In s
If Integer.TryParse(_s, i) And Convert.ToInt32(_s) <= 3 Then
System.Diagnostics.Debug.Print(_s)
End If
Next
string[] s = new string[4] { "1", "2", "3", "a" };
int i;
foreach (string _s in s)
{
if (int.TryParse(_s, out i) & Convert.ToInt32(_s) <=3)
{ System.Diagnostics.Debug.Print(_s); }
}
Dim a As Integer = 1
Dim b As Integer = 1
If a = 2 And b = Convert.ToInt32(Date.Now) Then '產生錯誤 : Invalid cast from 'DateTime' to 'Int32'.
Debug.Print("Hello!")
End If
int a= 1;
int b= 1;
if (a == 2 & b == Convert.ToInt32(DateTime.Now)) //產生錯誤 : Invalid cast from 'DateTime' to 'Int32'.
{ Console.WriteLine("Hello!"); }
Dim a As Integer = 1
Dim b As Integer = 1
If a = 2 AndAlso b = Convert.ToInt32(Date.Now) Then
Debug.Print("Hello!") 'Output "Hello!"
End If
int a= 1;
int b= 1;
if (a == 2 && b == Convert.ToInt32(DateTime.Now))
{ Console.WriteLine("Hello!"); } //Output "Hello!"
Dim a As Integer = 1
Dim b As Integer = 1
If a = 1 Or b = Convert.ToInt32(Date.Now) Then '產生錯誤 : Invalid cast from 'DateTime' to 'Int32'.
Debug.Print("Hello!")
End If
int a= 1;
int b= 1;
if (a == 1 | b == Convert.ToInt32(DateTime.Now)) //產生錯誤 : Invalid cast from 'DateTime' to 'Int32'.
{ Console.WriteLine("Hello!"); }
Dim a As Integer = 1
Dim b As Integer = 1
If a = 1 OrElse b = Convert.ToInt32(Date.Now) Then
Debug.Print("Hello!") 'Output "Hello!"
End If
int a= 1;
int b= 1;
if (a == 1 || b == Convert.ToInt32(DateTime.Now))
{ Console.WriteLine("Hello!"); } //Output "Hello!"
啟用 Windows Vista 資訊看板時，Visual Studio 2008 SP1 安裝失敗。
若要解決這個問題：
1. 以滑鼠右鍵按一下通知區域中的 [資訊看板] 圖示，位於工作列的最右邊。
2. 按一下 [結束]。
Well, you don't have to! LINQPad lets you interactively query databases in a modern query language: LINQ. Kiss goodbye to SQL Management Studio!
LINQPad supports everything in C# 4.0 and Framework 4.0:
And that's not all - there's also specific support for:
LINQPad is also a great way to learn LINQ: it comes loaded with 500 examples from the book, C# 4.0 in a Nutshell. There's no better way to experience the coolness of LINQ and functional programming.
And LINQPad is more than a LINQ tool: it's an ergonomic C#/VB/F# scratchpad that instantly executes any expression, statement block or program with rich output formatting – the ultimate in dynamic development. Put an end to those hundreds of Visual Studio Console projects cluttering your source folder!
Download LINQPad :
DataClass.infodata1_DataContext dc = new LINQPlayer.DataClass.infodata1_DataContext();
var select = (from c in dc.Contact where c.ContactID != null select new { c.ContactID , c.NameStyle, Name = (c.Title + ' ' + c.FirstName + ' ' + c.MiddleName + ' ' + c.LastName), c.EmailAddress, c.Phone, c.ModifiedDate }).Take(Convert.ToInt32(cboTake.SelectedItem)).Skip(Convert.ToInt32(cboSkip.SelectedItem));
dgv1.DataSource = select;
class DCClass
{
// 取得Customers的Table , 進行Table Mapping
[Table(Name = "Customers")]
public class CustomerDC
{
// Column : CustomerID
[Column(IsPrimaryKey = true)]
public string CustomerID { get; set; }
// Column : Name 並轉成 ContactName
[Column(Name = "ContactName")]
public string Name { get; set; }
// Column : City
[Column]
public string City { get; set; }
}
}
private void button2_Click(object sender, EventArgs e)
{
//建立IDbConnection
IDbConnection MyConnection = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\Nwind.mdb;User Id=admin;Password=;");
//建立dc為新的DataContext
DataContext dc = new DataContext(MyConnection);
//建立EntityType的Customers 並取得DCClass中的CustomerDC結構
Table<dcclass.customerdc> Customers = dc.GetTable<dcclass.customerdc>();
//可以直接使用LinQ語法去做Query了
DataGridView1.DataSource = from c in Customers where c.CustomerID.StartsWith("A") select new { MyCustomerID = c.CustomerID, MyCustomerName = c.Name, MyCity = c.City };
}
