?: Operator (Ternary) (C#)

C# > Operators > Ternary (?:)

Ternary (conditional) operator (?:) returns one of two values depending on the value of a Boolean expression.

The syntax for the ternary operator is

condition ? first_expression : second_expression;

Example:

namespace WindowsFormsApplication1

{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private string OddOrEven(int x)
        {
            return (x % 2 == 0) ? "Number is even" : "Number is odd";
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            string s;
            s = OddOrEven(10); // Number is even
            s = OddOrEven(11); // Number is odd
        }
    }
}

Verbatim String Literals (C#)

C# > Verbatim String Literals 

In a verbatim string literal, the characters between the delimiters are interpreted verbatim, the only exception being a quote-escape-sequence.

Suppose you want to set a string as following:

string path = "C:\\Programs\\MyProgram\\My.exe";

You can use the verbatim string literal character (@) to build the string exactly as it appears within the double quotation marks.

string path = @"C:\Programs\MyProgram\My.exe";

Escape sequences (C#)

C# > Escape sequences

The special escape character is the backslash character (\).

\" Display a double quotation mark.
\'  Display a single quotation mark.
\\  Display a backslash.

\0 Null

\a Alarm

\b Backspace

\f Form feed

\n Newline

\r Carriage return

\t Tab

\v Vertical tab

  

string msg = "Dan said: \"Hello world!\"";
Result is:
Dan said: "Hello world!"

string path = "C:\\MyDir";
Result is:
C:\MyDir

Filter DataTable with LINQ (Visual Basic)

VB.NET > Data > DataTable > Filter with LINQ

Use AsEnumerable method to return the input type DataTable as IEnumerable.
The CopyToDataTable method takes the results of a query and copies the data into a DataTable.






Example:

Public Class Form1

  Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    Dim dt As DataTable = New DataTable("table")
    dt.Columns.Add("id", Type.GetType("System.Int32"))
    dt.Columns.Add("name", Type.GetType("System.String"))

    Dim dr As DataRow = dt.NewRow()

    dr("id") = 1
    dr("name") = "john"
    dt.Rows.Add(dr)

    dr = dt.NewRow()

    dr("id") = 2
    dr("name") = "dan"
    dt.Rows.Add(dr)

    Dim filteredTable As DataTable = (From n In dt.AsEnumerable()

        Where n.Field(Of Int32)("id") = 1
                    Select n).CopyToDataTable()

    ComboBox1.DataSource = filteredTable
    ComboBox1.DisplayMember = "name"
    ComboBox1.ValueMember = "id"
  End Sub

End Class

Regular expression pattern Split method in C#

C# > Text > Regular Expressions > Split

Splits an input string into an array of substrings at the positions defined by a regular expression pattern.

Example:

string path = "some_text_words";

string[] substrings = Regex.Split(path, "_");

foreach (string match in substrings)

{}

Database Mail Views (SQL Server)

SQL Server > Catalog Views > Database Mail

These views are located in the msdb database.

Database Mail has views for displaying Database Mail e-mails information such as status of e-mails, any messages received and errors logged by Database Mail.

sysmail_allitems

Contains one row for each message processed by Database Mail.

Important columns

Name	Description
mailitem_id	Identifier of the mail item in the mail queue.
profile_id	The identifier of the profile used to send the message.
recipients	The e-mail addresses of the message recipients.
subject	The subject line of the message.
body	The body of the message.
sent_status	The status of the mail. Possible values are: sent - The mail was sent. unsent - Database mail is still attempting to send the message. retrying - Database Mail failed to send the message but is attempting to send it again. failed - Database mail was unable to send the message.
sent_date	The date and time that the message was sent.

sysmail_faileditems

Contains information about  messages were not successfully sent.
Has the same colums as but sent_status value is always failed.
To view the reason for the failure see onformation in the sysmail_event_log view.

sysmail_event_log

Contains one row for each message returned by the Database Mail system.
When troubleshooting Database Mail, search in sysmail_event_log view for events related to e-mail failures.

Important columns:

event_type	Errors, warnings, informational messages, success messages
log_date	The date and time the log entry is made.
description	The text of the message being recorded.
mailitem_id	Identifier of the mail item in the mail queue.

 

Set hour and minute to a date SQL Server

SQL Server > Datetime > Set hour and minute to a date

declare @d1 datetime

set @d1 = (Select DateAdd(hour, 6, cast(floor(cast(getdate() as float))as datetime)))

set @d1 = (Select DateAdd(minute, 45, @d1))

print @d1

Result:

Jan 23 2013 6:45AM

Full screen application (C#)

TopMost

Gets or sets a value indicating whether the form should be displayed as a topmost form.

private void Form1_Load(object sender, EventArgs e)

{
  this.MaximizeBox = false;
  this.MinimizeBox = false;
  this.TopMost = true;
  this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
  this.WindowState = System.Windows.Forms.FormWindowState.Maximized;
}

Stop Statement (VB.NET)

VB.Net > Statements > Stop

Stop is a programmatic alternative to setting a breakpoint and suspends the execution. When the debugger finds Stop statement, it breaks execution of the program.

Note: Unlike End, it does not close any files or clear any variables.

Example:

Dim i As Integer

Dim j As Integer
For i = 1 To 100
 j = i + 1
 Stop
Next i

With...End With Statement (VB.NET)

VB.NET > Statements > With...End With

Executes a series of statements that repeatedly refers to a single object or structure.

By using With...End With, you can perform a series of statements on a specified object without specifying the name of the object multiple times.

Example:

Public Class Form1

  Private Class Customer

    Public Property Id As String

    Public Property Name As String

  End Class

  Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    With New Customer

      .Id = 1

      .Name = "Elsoft"

      MessageBox.Show(.Name)

    End With

  End Sub

Temporary Tables (SQL Server)

SQL Server > Temporary tables

Local temporary tables

• visible only to their creators during the same connection to an instance of SQL Server
• deleted after the user disconnects from the instance of SQL Server
• local temporary table name is stared with hash ("#") sign.

Example

Create temporary table

Global temporary tables

• visible to any user and any connection after they are created
• deleted when all users that are referencing the table disconnect from the instance of SQL Server
• global Temporary tables name starts with a double hash ("##")

Get parent row RadGridView Telerik

Telerik > Windows Forms > Get parent row RadGridView

Example: Get parent row RadGridView Telerik

Dim oParentRow As GridViewDataRowInfo = grd.CurrentRow.ViewInfo.ParentRow

Terminate application (VB.Net)

VB.NET > Statements > End

End  force the application to stop running.

• closes files opened Open statement
• clears all the application variables

Example:

End application on button click

Public Class Form1

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    End Sub

    Private Sub btn_Click(sender As Object, e As EventArgs) Handles btn.Click

        If MsgBox("Do you want to exit?", MsgBoxStyle.YesNo) = MsgBoxResult.Yes Then
            End
        End If
    End Sub

End Class