Posts Tagged Catch

Encryption and Decryption of strings with C#

Well I am checking out the Beale Street Historic District for the first time in Memphis, TN tonight. I have heard a lot about it since my arrival here so am excited to get to go. I think it will be fun.

Of course this would come up. I had written this previously in vb.net and I had the opportunity to use it again today. Of course in doing so, I discovered a bad coding practice violation I had committed. I had failed to return a value in my function’s Catch block of my code. C# doesn’t let you off the hook so easily and will bug you till you fix it. As noted previously, topic is encryption and decryption of strings. It is straightforward but you might find it useful. Simply pass in the string you want to encrypt/decrypt and the key you want to use.

using System;
using System.IO;
using System.Text;
using System.Security.Cryptography;
public class Crypto
{
    private static TripleDESCryptoServiceProvider DES = new TripleDESCryptoServiceProvider();
    private static MD5CryptoServiceProvider MD5 = new MD5CryptoServiceProvider();
    public static byte[] MD5Hash(string value)
    {
        return MD5.ComputeHash(ASCIIEncoding.ASCII.GetBytes(value));
    }
    public static string Encrypt(string stringToEncrypt, string key)
    {
        DES.Key = Crypto.MD5Hash(key);
        DES.Mode = CipherMode.ECB;
        byte[] Buffer = ASCIIEncoding.ASCII.GetBytes(stringToEncrypt);
        return Convert.ToBase64String(DES.CreateEncryptor().TransformFinalBlock(Buffer, 0, Buffer.Length));
    }
    public static string Decrypt(string encryptedString, string key)
    {
        try
        {
            DES.Key = Crypto.MD5Hash(key);
            DES.Mode = CipherMode.ECB;
            byte[] Buffer = Convert.FromBase64String(encryptedString);
            return ASCIIEncoding.ASCII.GetString(DES.CreateDecryptor().TransformFinalBlock(Buffer, 0, Buffer.Length));
        }
        catch (Exception ex)
        {
            MessageBox.Show(“Invalid Key”, “Decryption Failed”, MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
        }
// Inserted the following ‘return’ since all code paths must return a value in C#:
        return null;
    }
}

And now it’s usage…..

public class Form1
{
    private void Button1_Click(object sender, System.EventArgs e)
    {
        string key = Microsoft.VisualBasic.Interaction.InputBox(“Enter a Key:”, “”, “”, -1, -1);
        Label1.Text = Crypto.Encrypt(TextBox1.Text, key);
        TextBox1.Clear();
    }
    private void Button2_Click(object sender, System.EventArgs e)
    {
        string key = Microsoft.VisualBasic.Interaction.InputBox(“Enter a Key:”, “”, “”, -1, -1);
        TextBox1.Text = Crypto.Decrypt(Label1.Text, key);
    }

    }


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Check if SQL Database Exists with C#

Good Morning! I wanted to give a shout out to another blogger who linked to us yesterday here. It was so nice of him you know? Just amazing, the generosity of some folks out there!

Today’s code was a rewrite of the vb.net code here but using C#. One thing of note is that the Using keyword has a completely different meaning in C# so thus has been removed. It wasn’t really needed anyway.

Anyway, so make it a great day!

public Boolean testDatabaseExists(string server, string database)
        {
            String connString = (“Data Source=” + (server + “;Initial Catalog=master;Integrated Security=True;”));
            String cmdText = (“select * from master.dbo.sysdatabases where name=\'” + (database + “\'”));
            Boolean bRet;

            System.Data.SqlClient.SqlConnection sqlConnection = new System.Data.SqlClient.SqlConnection(connString);
            System.Data.SqlClient.SqlCommand sqlCmd = new System.Data.SqlClient.SqlCommand(cmdText, sqlConnection);
           
            try
            {
            sqlConnection.Open();
            System.Data.SqlClient.SqlDataReader reader = sqlCmd.ExecuteReader();
            bRet = reader.HasRows;
            sqlConnection.Close();
            }
            catch (Exception e)
            {
            bRet = false;
            sqlConnection.Close();
            MessageBox.Show(e.Message);
            return false;
            } //End Try Catch Block
                      
           
            if (bRet == true)
            {
                MessageBox.Show(“DATABASE EXISTS”);
                return true;
            }
            else
            {
                MessageBox.Show(“DATABASE DOES NOT EXIST”);
                return false;
            } //END OF IF

           
        } //END FUNCTION

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Create a Share on Remote Machine using WMI with vb.net

This code was used to create a share on a remote machine a while back for the purpose of automating a function that had previously required a network guy at the company to actually touch the machine which of course they didn’t like to do (it required work on their part). But it was ok. I didn’t mind as it wasn’t that hard. WMI makes it easy to do.

I have been involved with a series of technical discussions with some folks at various companies lately. My most embarrassing moment yesterday was when I stumbled on my words when asked about polymorphism. I actually used the words “parallel universe” in conjunction with this! Can you imagine? I got to think better on my feet. But its all good. Have a great day!

Public Sub CreateShare(ByVal strShareName As String, ByVal strPath As String, ByVal computername As String, ByVal shareinfo As String)
        Try
            Dim objSWbemServices As Object
            Dim objSWbemObject As Object
            Dim colSWbemObject As Object
            Dim intRet As Integer
            Dim blnExists As Boolean
            Dim objSWbem As Object

            objSWbemServices = GetObject(“winmgmts://” + computername + “/root/cimv2”)

            colSWbemObject = objSWbemServices.InstancesOf(“Win32_Share”)

            For Each objSWbem In colSWbemObject
                If (objSWbem.name = strShareName) Then
                    blnExists = True
                    Exit For
                Else
                    blnExists = False
                End If
            Next

            If (blnExists = False) Then
                objSWbemObject = objSWbemServices.Get(“Win32_Share”)
                intRet = objSWbemObject.Create(strPath, strShareName, 0, 25, shareinfo)
                System.Console.WriteLine(“Share has been created on : ” + computername)
                System.Console.WriteLine(“ShareName : ” + ShareName + ”   SharePath : ” + SharePath + ”   ShareInfo : ” + shareinfo)
            Else
                System.Console.WriteLine(“Share is already present on computer : ” + computername)
                System.Console.WriteLine(“ShareName : ” + ShareName + ”   SharePath : ” + SharePath + ”   ShareInfo : ” + shareinfo)
            End If
        Catch ex As Exception
            System.Console.Write(“Error occured while trying to create shares on remote pc : ” + computername + vbCrLf + “Check if you have the necessary rights and/or that the pc is turned on.” + vbCrLf + ex.ToString)
            System.Console.WriteLine(“ShareName : ” + ShareName + ”   SharePath : ” + SharePath + ”   ShareInfo : ” + shareinfo)
        End Try

    End Sub

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Getting Images from Microsoft Office Document Imaging (MODI) with vb.net

Hello! It has been a long time since my last blog post and I am happy to be getting back to this. I have missed writing this blog more than you have missed me I guarantee it!

That being said, now that this blog has resumed there will be a few changes. The landscape has changed a bit since my last blog entry. While I will still focus primarily on vb.net code I will also be including what I am working on that is WPF and C# related as well as other .NET related topics. Why? Simply because as my skillset has expanded I wanted to share what I have learned and am learning with you as well. I hope you won’t mind!

Today’s topic revolves around getting images from Microsoft Office Document Imaging (MODI). As you recall I have done a lot of Office automation over the years and I was asked to do this for a friend. As I said, it is good to be back!

add a reference -> Com -> Microsoft Office Document Imaging

Private Sub ConvertMdi2Tif(ByVal ModiFilePath As String)
Dim miDoc As New MODI.Document
Dim myViewer As New MODI.MiDocView
Dim myImg As MODI.Image
Try
Dim Folder As New DirectoryInfo(ModiFilePath)
pbReportGenerate.Minimum = 0
pbReportGenerate.Maximum = Folder.GetFiles(“*.MDI”).Length
pbReportGenerate.Step = 1
pbReportGenerate.Value = pbReportGenerate.Minimum
For Each File As FileInfo In Folder.GetFiles(“*.MDI”)
miDoc.Create(File.FullName)
myViewer.Document = miDoc
For i As Long = 0 To miDoc.Images.Count – 1
Dim tempDoc As New MODI.Document
myImg = miDoc.Images(i)
tempDoc.Create()
tempDoc.Images.Add(myImg, Nothing)
tempDoc.SaveAs(TIFPath & “\” + GetFileNameWithoutExtension(File.FullName) & i & “.Tif”, MiFILE_FORMAT.miFILE_FORMAT_TIFF_LOSSLESS, MiCOMP_LEVEL.miCOMP_LEVEL_HIGH)
tempDoc.Close()
tempDoc = Nothing
Exit For
Next
pbReportGenerate.PerformStep()
Application.DoEvents()
Next
miDoc.Close()
miDoc = Nothing
myViewer.Document = Nothing
myViewer = Nothing
Catch ex As Exception
MsgBox(ex.Message)
End Try
GC.Collect()
End Sub

Private Sub ConvertTif2Bmp(ByVal TIFFilePath As String)
Dim Folder As New DirectoryInfo(TIFFilePath)
Dim index As Long = 0
pbReportGenerate.Minimum = 0
pbReportGenerate.Maximum = Folder.GetFiles(“*.TIF”).Length
pbReportGenerate.Step = 1
pbReportGenerate.Value = pbReportGenerate.Minimum
For Each File As FileInfo In Folder.GetFiles(“*.TIF”)
GC.WaitForPendingFinalizers()
Dim streamBinary As New FileStream(File.FullName, FileMode.Open)
Dim g As System.Drawing.Image = System.Drawing.Image.FromStream(streamBinary)
Dim imgOutput As New Bitmap(g, g.Width, g.Height)

Dim qualityEncoder As Encoder = Encoder.Quality
Dim ratio As EncoderParameter = New EncoderParameter(qualityEncoder, 40)
Dim codecParams As New EncoderParameters(1)
codecParams.Param(0) = ratio
‘bmp.Save(fileName, jpegCodecInfo, codecParams)
Dim encoder1 As ImageCodecInfo = GetEncoderInfo(“image/bmp”)
imgOutput.Save(BMPPath + “\” + GetFileNameWithoutExtension(File.FullName) + “.” & System.Drawing.Imaging.ImageFormat.Bmp.ToString, encoder1, codecParams)
streamBinary.Close()
streamBinary = Nothing
g.Dispose()
g = Nothing
imgOutput.Dispose()
imgOutput = Nothing
pbReportGenerate.PerformStep()
Application.DoEvents()
Next
GC.Collect()
End Sub


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