Mortgage Calculator Error - C# Discussion Boards

Subin Mavunkal20-Mar-12 23:17

20-Mar-12 23:17

You can use SmartPaster addin for visual studio.Copy the text you needed and paste it as string builder.Here is the code and installer

http://www.martinwilley.com/blog/2010/06/06/SmartPasteIn2010.aspx[^]

Re: Appending Quations to a string

Pete O'Hanlon21-Mar-12 3:53

Pete O'Hanlon

21-Mar-12 3:53

An alternative approach is to use a list of strings instead of a StringBuilder to build your list and then concatenate them as you need. Here's one way to do this:

public class FormattedStrings : List<string>()
{
  public override string ToString()
  {
    StringBuilder sb = new StringBuilder();
    bool started = false;
    foreach (string item in this)
    {
      if (started)
      {
        sb.AppendFormat(",\"{0}\"", item);
      }
      else
      {
        started = true;
        sb.AppendFormat("\"{0}\"", item);
      }
    }

    return sb.ToString();
  }
}

I am assuming that you have assigned the @ symbol when you built your StringBuilder.

*pre-emptive celebratory nipple tassle jiggle* - Sean Ewington

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

Re: Appending Quations to a string

PIEBALDconsult21-Mar-12 4:53

PIEBALDconsult

21-Mar-12 4:53

Ew, yuck, duplicated code. Dead | X|

Needless boolean, needless if/else.

Stick the comma on the end and decrement it off when you're done.

Re: Appending Quations to a string

Pete O'Hanlon21-Mar-12 5:59

Pete O'Hanlon

21-Mar-12 5:59

To be fair, this was just knocked up in the CP editor and doesn't reflect what I would push out the door.

I did look at doing it your way, but saw that you'd already posted that so it seemed that there wasn't much point to showing something that was already done - this is purely to stimulate the mind into thinking of other ways of solving the problem.

*pre-emptive celebratory nipple tassle jiggle* - Sean Ewington

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

Image Encryption

Hinnawi8720-Mar-12 5:14

Hinnawi87

20-Mar-12 5:14

I want to encrypt image by other image using Xor operation in c# as follow:

private byte[] EncypteXoRImage(byte[] inputImage, byte[] byImage)
{
byte[] Result = (byte[])inputImage.Clone();
if (byImage == null)
return Result;
for (int k = inputImage.Length / 3; k < inputImage.Length; k++)
{

Result.SetValue(Convert.ToByte((byte)Result.GetValue(k) ^ (byte)byImage.GetValue(k % byImage.Length)), k);

}
return Result;
}
where inputImage is picture which i want to encrypt,the problem is when i want to display encrypted picture on the picturebox,the result is:
the encrypted part was displayed by a gray background

Re: Image Encryption

harold aptroot20-Mar-12 5:37

harold aptroot

20-Mar-12 5:37

Code doesn't seem to make sense. Could you try this?

private byte[] EncypteXoRImage(byte[] inputImage, byte[] byImage)
{
    if (byImage == null)
        return (byte[])inputImage.Clone();
    byte[] result = new byte[inputImage.Length];
    for (int k = 0; k < result.Length; k++)
    {
        result[k] = (byte)(inputImage[k] ^ byImage[k]);
    }
    return result;
}

Re: Image Encryption

OriginalGriff20-Mar-12 5:40

OriginalGriff

20-Mar-12 5:40

You can make your method a lot easier to understand by using actual array references instead of GetValue and SetValue - and also by throwing awy unnecessary conversions:

private byte[] EncypteXoRImage(byte[] inputImage, byte[] byImage)
    {
    byte[] Result = (byte[])inputImage.Clone();
    if (byImage == null)
        return Result;
    for (int k = inputImage.Length / 3; k < inputImage.Length; k++)
        {
        Result[k] ^= byImage[k % byImage.Length];
        }
    return Result;
    }

However, it will have no affect on your problem - since the code is equivalent.

Out of interest, I tried this with two of my pictures:

private void myButton_Click(object sender, EventArgs e)
    {
    Image i = Image.FromFile(@"D:\Temp\MyPic.jpg");
    Image j = Image.FromFile(@"D:\Temp\MyOtherPic.jpg");
    pictureBox1.Image = i;
    pictureBox2.Image = j;
    MemoryStream msI = new MemoryStream();
    i.Save(msI, System.Drawing.Imaging.ImageFormat.Bmp);
    MemoryStream msJ = new MemoryStream();
    j.Save(msJ, System.Drawing.Imaging.ImageFormat.Bmp);
    byte[] res = EncypteXoRImage(msI.ToArray(), msJ.ToArray());
    MemoryStream msK = new MemoryStream(res);
    Image k = Image.FromStream(msK);
    pictureBox3.Image = k;

    }
private byte[] EncypteXoRImage(byte[] inputImage, byte[] byImage)
    {
    byte[] Result = (byte[])inputImage.Clone();
    if (byImage == null)
        return Result;
    for (int k = inputImage.Length / 3; k < inputImage.Length; k++)
        {
        Result[k] ^= byImage[k % byImage.Length];
        }
    return Result;
    }

Apart from being a pretty useless encryption technique (I could work out what both pictures were from the composite, pretty much, in the same way that I can read Captcha codes), it worked - I did not get a solid grey background with either version of your method.

So I assume it is your conversion from Image to byte array that is at fault.

Ideological Purity is no substitute for being able to stick your thumb down a pipe to stop the water

Mortgage Calculator Error

Xonel20-Mar-12 3:32

Xonel

20-Mar-12 3:32

Hi,

I have this error in my code that am having difficulties in rectifying it. Initially, my code looked like this..

private void CalculateTheMortgage()
      {
          //  (Loan Value) *  (1 + r/12) ^ p =  (12x / r)  *  ((1 + r/12)^p - 1)
          // payment = (((Loan Value) *  (1 + r/12) ^ p) * r)/ (12 * ((1 + r/12)^p - 1)));
          double loanAmount = (double)txtLoanAmount.CurrentValue;  // price of total mortgage before down payment
          double taxesPerYear = (double)txtPropertyTax.CurrentValue; // this will divided by 12 and added to the monthly payment
          double downPayment = (double)txtDownPayment.CurrentValue; // down payment will be subtracted from the loan
          double interestRate = (double)udInterest.Value / 100;  // calculate interest from 100%
          double termOfLoan = (double)(udTerm.Value * 12); // monthly term
          double propertyTax = (double)txtPropertyTax.CurrentValue;
          double insurance = (double)txtInsurance.CurrentValue;

         double payment =  (loanAmount - downPayment) * (Math.Pow((1 + interestRate/12), termOfLoan) * interestRate)/(12 * (Math.Pow((1+interestRate/12), termOfLoan) - 1));

         // add on a monthly property tax
         payment = payment + (propertyTax + insurance) / 12;

         txtPayment.CurrentValue = (int)payment;
      }

and i changed it a little to this...

private void CalculateTheMortgage()
      {
          //  (Loan Value) *  (1 + r/12) ^ p =  (12x / r)  *  ((1 + r/12)^p - 1)
          // payment = (((Loan Value) *  (1 + r/12) ^ p) * r)/ (12 * ((1 + r/12)^p - 1)));
          double loanAmount = Convert.ToDouble(txtLoanAmount.Text);// price of total mortgage before down payment
          double taxesPerYear = Convert.ToDouble(txtPropertyTax.Text); // this will divided by 12 and added to the monthly payment
          double downPayment = Convert.ToDouble(txtDownPayment.Text); // down payment will be subtracted from the loan
          double interestRate = (double)udInterest.Value / 100;  // calculate interest from 100%
          double termOfLoan = (double)(udTerm.Value * 12); // monthly term
          double propertyTax = Convert.ToDouble(txtPropertyTax.Text);
          double insurance = Convert.ToDouble(txtInsurance.Text);


          double payment = (loanAmount - downPayment) * (Math.Pow((1 + interestRate / 12), termOfLoan) * interestRate) / (12 * (Math.Pow((1 + interestRate / 12), termOfLoan) - 1));

          // add on a monthly property tax
          payment = payment + (propertyTax + insurance) / 12;


          txtPayment.CurrentValue = (int)payment;
      }

which removed the error message below. Now i wanna change this

txtPayment.CurrentValue = (int)payment;

piece of code so that the same error cannot occur again. There is a blue line under 'CurrentValue'
This is the error am getting...

'System.Windows.Forms.TextBox' does not contain a definition for 'CurrentValue' and no extension method 'CurrentValue' accepting a first argument of type 'System.Windows.Forms.TextBox' could be found (are you missing a using directive or an assembly reference?)

Please help me here
Thanks

Re: Mortgage Calculator Error

PIEBALDconsult20-Mar-12 3:37

PIEBALDconsult

20-Mar-12 3:37

textbox.Text ?

Re: Mortgage Calculator Error

Xonel20-Mar-12 3:44

Xonel

20-Mar-12 3:44

When i write it like this

txtPayment.Text = (int)payment;

am getting this error

Cannot implicitly convert type 'int' to 'string'

with a blue line under '(int)'

Re: Mortgage Calculator Error

ZurdoDev20-Mar-12 4:33

ZurdoDev

20-Mar-12 4:33

Don't convert it to int when trying to put it into a textbox.

There are only 10 types of people in the world, those who understand binary and those who don't.

Re: Mortgage Calculator Error

JF201520-Mar-12 3:48

JF2015

20-Mar-12 3:48

txtPayment.Text = payment.ToString();

or:

txtPayment.Text = payment.ToString("0.00 $");

Re: Mortgage Calculator Error

Xonel20-Mar-12 3:55

Xonel

20-Mar-12 3:55

Can't believe it was that simple....

Thanks a lot!
It worked..
Smile | :)

Re: Mortgage Calculator Error

V.20-Mar-12 3:54

20-Mar-12 3:54

There are many things wrong here.

Convert.ToDouble

will work and is preferable of

(double)somevalue

but the best method is

double.TryParse or int.TryParse

Secondly you need to use

txtPayment.Text = payment.ToString();

and make sure payment is not null.
If you do want an integer, you need to indeed first cast the double to an integer and then that integer to a string (or use round and floor functions)

Why do you cast to double in these cases?

double interestRate = (double)udInterest.Value / 100;  // calculate interest from 100%
double termOfLoan = (double)(udTerm.Value * 12); // monthly term

What is this code for? Own project, a book, homework?

Re: Mortgage Calculator Error

DaveyM6920-Mar-12 5:08

DaveyM69

20-Mar-12 5:08

Very minor, but...

V. wrote:
make sure payment is not null

payment is a double (not double?) so cannot be null Wink | ;)

Dave

Binging is like googling, it just feels dirtier.
Please take your VB.NET out of our nice case sensitive forum.
Astonish us. Be exceptional. (Pete O'Hanlon)

BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)

Re: Mortgage Calculator Error

V.20-Mar-12 6:20

20-Mar-12 6:20

You're absolutely right.

Re: Mortgage Calculator Error

PIEBALDconsult20-Mar-12 6:07

PIEBALDconsult

20-Mar-12 6:07

V. wrote:
and is preferable

No it isn't.

V. wrote:
the best method is

Not when a cast will do.

Re: Mortgage Calculator Error

BobJanova21-Mar-12 3:21

BobJanova

21-Mar-12 3:21

double.Parse is not equivalent to a double cast. One does a string-to-number conversion, the other does a number-to-number conversion. You can use Convert.ToDouble to do either, but I disagree that it's preferable for either scenario: use the mechanism that makes sense in context. A cast translates to a single IL opcode, not a whole method call, after all.

Program to find color of the pixels being selected in a picture

Supztermc20-Mar-12 1:54

Supztermc

20-Mar-12 1:54

Hello!

It's been only a few weeks since I have started to learn WPF, and I came across some assignments that needed color changing in the images being generated. For this, I was able to use radio buttons and get away with it, but I am interested to find out about using colour pickers.

Any idea as to how? Please share with me. I would appreciate it if the app is really simple though, because I am just an enthusiastic beginner. Unsure | :~