Parse Excel file using vb.net

The following method will load excel file in datareader which will be inserted to Sql server via Sqlbulkcopy.


Imports Microsoft.Office.Interop
Imports System.Data.OleDb
Imports System.Data.SqlClient


Public Class clsLoadExcel

Function Process(ByVal filePath As String) As Boolean

Dim objExcelConn As _
New System.Data.OleDb.OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" & filePath & ";Extended Properties=""Excel 12.0 Xml;HDR=Yes""")

Dim objQuery As String
Dim objCMD As OleDbCommand
Dim objDR As OleDbDataReader

Dim sqlConn As New SqlConnection
Dim sqlCmd As SqlCommand = New SqlCommand(sqlConn)
Dim sqlBCopy As New SqlBulkCopy(sqlConn)

sqlConn.ConnectionString = "data source=servername;Integrated security=true;Initial Catalog=db;"

objQuery = "SELECT * FROM [Sheet1$]" 'you can change your sheet name

Try
objCMD = New OleDbCommand(objQuery, objExcelConn)
objExcelConn.Open()          
objDR = objCMD.ExecuteReader

' open sql connection
sqlConn.Open()

' now write to sql
sqlBCopy.DestinationTableName = "TempTable"
sqlBCopy.WriteToServer(objDR)
       
Catch ex As Exception

Finally

If Not IsNothing(objDR) Then

objDR.Close()
End If

sqlConn.Close()
sqlBCopy.Close()
End Try

End Function

End Class

Read file in vb.net

One way

  Dim data As String

        Using sr As New StreamReader("C:\test.txt")
            Do
                data = sr.ReadLine()
                If Not data Is Nothing Then
                    ' do some parsing
                End If
                Console.WriteLine(data)
            Loop Until data Is Nothing
        End Using

2nd way - READ it ALL

Imports System
Imports System.IO

Class ReadALLFile
    Public Shared Sub Main()
        Try 
            Using sr As New StreamReader("TestFile.txt")
                Dim line As String
                line = sr.ReadToEnd()
                Console.WriteLine(line)
            End Using 
        Catch e As Exception         
            Console.WriteLine(e.Message)
        End Try 
    End Sub 
End Class

Read file Character by Character in vb.net

Dim currChar As Char
Dim data As String

  Using sr As New StreamReader("C:\test.txt")
            Do While sr.Peek <> -1
                currChar = Chr(sr.Read)
                data = data & currChar
                Console.WriteLine(data)
            Loop
   End Using

match ANYTHING using regular expression

Hi,

If you looking a way to match anything in .net using regular expression, the tool you need is:

(?s)

This mean anything including newline as well.

Here is how to use it:
(?s).*    -- comment: Replace angle brackets and mystring word with your word.

HTH.

Convert nvarchar to int in SQL

If your table has nvarchar column and there is integer data in this column , then inserting that data into int column type is not a problem.
But if data is float, then the data need to be converted to float datatype before cast to int to insert into int column type.

Example:
SELECT SUM(CAST(amount AS INT)),  title   FROM books GROUP BY title
...will give you:

Conversion failed when converting the nvarchar value '4500.00' to data type int.

Correct way

4500.00 is not integer so CAST via float first

sum(CAST(CAST(amount AS float) AS INT))

Why float?

• no idea of precision or scale across all rows
• empty string will cast to zero for float, fails on decimal
• float accepts stuff like 7E-02, fails on decimal 

HTH

STATISTICS_NORECOMPUTE in Rebuild Index

It specifies whether distribution statistics are recomputed. The default is OFF.

ON

Out-of-date statistics are not automatically recomputed.

OFF

Automatic statistics updating are enabled.

Indeed, statistics are recomputed during the index rebuild.

Dont think that it stops SQL Server from updating the statistics at the time of a rebuild; that is NOT what it does. 
Statistics are ALWAYS updated at the time of a REBUILD; this cannot be turned off (nor would you want to).

Instead, STATISTICS_NORECOMPUTE stops the database-wide auto-updating from updating the specific statistics for an index (or column-level statistic) that was created (or rebuilt) with this option turned on.

STATISTICS_NORECOMPUTE – When would anyone want to use it?

HTH

Delegates, Invoke, InvokeRequired

Question: What is InvokeRequired? Why this word is so difficult and what is it do? 

Answer: InvokeRequired is a property of a control which tells whether or not you can safely access the control. It is a boolean to check if you are on the UI thread before you try to update a form or control from a worker thread. 

If the property is True, then an invocation is required to access the control as the caller is on different thread than the one that owns the control's handle.

The invocation is performed by calling the control's Invoke or BeginInvoke method. 
You create a delegate, which is an object that contains the reference to a method. Then we pass this delegate to Invoke or BeginInvoke method which essentially call the reference method again but on thread that owns the control's handle.

Summary:
InvokeRequired asks 'Am I on the right thread?', if so carry on, else I need a delegate.

I got help and understanding of this from: 

Accessing Controls from Worker Threads

HTH.