The type initializer for ‘System.Data.SqlClient.SqlConnection’ threw an exception

I was getting the above error in one of my windows application. Was because of some section getting repeated in the app.config file.

Removing the duplicate section information from the app.config resolved the issue.

Preventing your system from getting auto locked

Within most of the organization, there is a default setting that after a few minutes have escaped, the system gets locked itself, if system is left unattended. Well to prevent this i have written a small utility (windows application) which periodically sends user input to the system, making it to believe that some mouse movement has been made and thus stopping the system from getting locked.

Here we would be calling SendInput function within user32.dll

The SendInput function synthesizes keystrokes, mouse motions, and button clicks and that is what we need.

http://msdn.microsoft.com/en-us/library/ms646310.aspx

This is useful in case we are giving presentation or else reading some documents …

Following is the code for the same

1) Create a new windows application in C#

2) Add a button named btn_Unlock to it and a timer control named timer1.

3) Set enabled to false and interval to 120000 for timer control.

4) Put the following code to your form class

public partial class frmKU : Form

{

public
frmKU()

{

InitializeComponent();

}

[DllImport("User32.dll", SetLastError = true)]

public static extern int SendInput(int
nInputs, ref INPUT
pInputs, int cbSize);

public struct INPUT

{

public
int type;

public
MOUSEINPUT mi;

}

public struct MOUSEINPUT

{

public
int dx;

public
int dy;

public
int mouseData;

public
int dwFlags;

public
int time;

public
int dwExtraInfo;

}

// Call the
API

int
resSendInput;

private
void btnUnlock_Click(object
sender, EventArgs e)

{

timer1.Enabled = true;

INPUT
input = new INPUT();

resSendInput = SendInput(5, ref input, Marshal.SizeOf(input));

}

private
void timer1_Tick(object
sender, EventArgs e)

{

INPUT
input = new INPUT();

resSendInput = SendInput(5, ref input, Marshal.SizeOf(input));

}

}

 

Bye …

Unable to find a version of the runtime to run the application

I was facing the problem while trying to run one of my windows application created in Visual studio 2005 using .NET framework 2.0.

Few days back the application was running fine and today it on trying to run it i was getting the error.

The way it solved for me was to again open the project in solution explorer in visual studio and rebuilding it.

Bye,..

Saving and Retrieving richtextbox control’s content (.rtf file) in database

Let’s start with a very simple application.

Drop OpenFileDialog control in the application.

When user click on Pick File button using OpenFileDialog he will select a rtf file to display in richtextbox control.

The content of richtextbox control will be saved in the sql server table.

This is how our table looks like.

File content is the image data type column where we will store our rtf content.

<!–[if gte vml 1]> <![endif]–>

Put the following code in Pick file button click.

if(openFileDialog1.ShowDialog() == DialogResult.OK)

{

try

{

rtfContent.LoadFile(openFileDialog1.FileName);

}

catch(Exception ex)

{

MessageBox.Show(ex.Message);

}

}

Put the following code in Save Button Click

SqlConnection conn=new SqlConnection(“Data Source=D-0824;Initial Catalog=WordInterOp; uid=sa;pwd=sa;”);

SqlCommand cmd=new SqlCommand();

cmd.CommandText = “Insert into RtfStore (fileName,fileContent) values ( @fname,@fcontent)”;

cmd.Connection=conn;

SqlParameter fileName=new SqlParameter(“@fname”,openFileDialog1.SafeFileName);

rtfContent.SaveFile(@”c:\temp.rtf”, RichTextBoxStreamType.RichText);

FileStream stream = new FileStream(@”c:\temp.rtf”, FileMode.Open, FileAccess.Read);

int size = Convert.ToInt32(stream.Length);

Byte[] rtf = new Byte[size];

stream.Read(rtf, 0, size);

SqlParameter fileContent=new SqlParameter();

fileContent.ParameterName=”@fcontent”;

fileContent.SqlDbType=SqlDbType.Image;

fileContent.Size=rtf.Length;

fileContent.Value=rtf;

cmd.Parameters.Add(fileName);

cmd.Parameters.Add(fileContent);

conn.Open();

int success=cmd.ExecuteNonQuery();

if(success==1)

{

MessageBox.Show(“Entered data successfully”);

}

openFileDialog1.SafeFileName- To get the name of file instead of the complete path.

rtfContent.SaveFile- Saving the content of the control in a rtf file.

RichTextBoxStreamType.RichText- This tells that we are saving richtext having some formatting and not just plain text.

Finally through filestream we are reading that file and saving it’s content in our sqlserver table.

Similary to read the rtf content from the database and display it in Richtextbox control, this is what we need to do

// cmd.commandText=”select fileContent from RtfStore where filename=’xyz’ “;

SqlDataReader dr =  cmd.ExecuteReader();

if (dr.Read())

{

Byte[] rtf = new Byte[Convert.ToInt32((dr.GetBytes(0, 0,

null, 0, Int32.MaxValue)))];

long bytesReceived = dr.GetBytes(0, 0, rtf, 0, rtf.Length);

ASCIIEncoding encoding = new ASCIIEncoding();

rtfContent.Rtf = encoding.GetString(rtf, 0, Convert.ToInt32(bytesReceived));

}

Bye

Working with ListBox in .Net Windows Application

Say we want to implement some functionality as shown in the image below in our windows form

Using >> button we want to move values from optional sections to mandatory sections list box and vice versa using << button. But we don’t want the sections which are mandatory to move to optional list box.

Finally we can rearrange items in the Mandatory list box using up and down buttons.

Let’s see the code for all this

Our listboxes are named lstOptional and lstMandatory

>> button is named btnSelect

<< button is named btnDeSelect

When button >>(btnSelect is clicked)

private void btnSelect_Click(object sender, EventArgs e)
{

// if there are no item in lstOptional Listbox return

if (lstOptional.Items.Count == 0)
{

return;
}

// if some item is selected in the lstOptional Listbox check if we already have it in lstMandatory

// if it is there or nothing is selected than return

int g = lstMandatory.FindStringExact(lstOptional.Text);
if(g>-1||lstOptional.Text ==”")
{
return;
}

// finally add that item to lstMandatory, refresh it to make it appear and remove it from lstOptional

lstMandatory.Items.Add(lstOptional.Text );
lstMandatory.Refresh();
lstMandatory.Text = “”;
lstOptional.Items.Remove(lstOptional.Text);
}

When button << DeSelect is clicked

private void btnDeSelect_Click(object sender, EventArgs e)
{

// if nothing is selected in lstMandatory just put the focus over the listbox

if (lstMandatory.Text == “”)
{
lstMandatory.Focus();
return;
}

// checking if the selected item is mandatory on.

// Here we have saved the mandatory items in a hidden listbox on form load

int g = lstHidden.FindStringExact(lstMandatory.Text);
if (g > -1)
{
MessageBox.Show(“This section is mandatory”,”Information”);
}
else
{
lstOptional.Items.Add(lstMandatory.Text);
lstMandatory.Items.Remove(lstMandatory.Text);
}
}

When button Up is clicked we need to move the selected item in upward direction

int selectedItemIndex = lstMandatory .SelectedIndex;
String selectedItemText = lstMandatory .Text;
if (selectedItemIndex != 0)
{
lstMandatory .Items.RemoveAt(selectedItemIndex);
lstMandatory .Items.Insert(selectedItemIndex – 1, selectedItemText);
lstMandatory .SelectedIndex = selectedItemIndex – 1;
}
lstMandatory .Refresh();
lstMandatory .Focus();

Finally when button Down is clicked

int selectedItemIndex = lstMandatory.SelectedIndex;
String selectedItemText = lstMandatory.Text;
int total = lstMandatory.Items.Count;
if (selectedItemIndex < total – 1)
{
lstMandatory.Items.RemoveAt(selectedItemIndex);
lstMandatory.Items.Insert(selectedItemIndex + 1, selectedItemText);
lstMandatory.SelectedIndex = selectedItemIndex + 1;
}
lstMandatory.Refresh();

Bye