error Input string was not in a correct format

Question

2.50/5 (2 votes)

See more:

i have a form responsible for adding student classwork, IA, exams and give the result. base on the result it generates the Grade. my cdoes are working right but i keep getting this error message when i click on the save button "Input string was not in a correct format" please help me out

code behined the form

C#

 private void btnSave_Click(object sender, EventArgs e)
        {
            SqlConnection conn = new SqlConnection(ConfigurationSettings.AppSettings["ConnectionString"]);
            conn.ConnectionString = "Data Source=MICKY-PC;Initial Catalog=SMS;User ID=sa;Password=mike";

            //save data
            try
            {

                clsStudentaccademics person = new clsStudentaccademics();

                var
                _with1 = person;
_with1.classworkfcs = txtFcs_classwork.Text;
                _with1.iafcs = txtFcs_ia.Text;
                _with1.examsfcs = txtFcs_exams.Text;
                _with1.totalsfcs = txtFcs_totals.Text;
                _with1.gradingfcs = txtFcs_grading.Text;

C#

_with1.saveRegister();
                clearScreen();
                MessageBox.Show("Record is successfully Added");

            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

codes performing the calculation

C#

private void txtFcs_exams_TextChanged(object sender, EventArgs e)
        {
            try
            {
                double classworkFcs, iaFcs, examsFcs, totalsFcs;

                classworkFcs = Convert.ToDouble(txtFcs_classwork.Text);
                iaFcs = Convert.ToDouble(txtFcs_ia.Text);
                examsFcs = Convert.ToDouble(txtFcs_exams.Text);


                totalsFcs = classworkFcs + iaFcs + examsFcs;
                txtFcs_totals.Text = totalsFcs.ToString();

                if (totalsFcs >= 75)
                {
                    txtFcs_grading.Text = "   A";
                }
                else if (totalsFcs >= 70)
                {
                    txtFcs_grading.Text = "   B";
                }
                else if (totalsFcs >= 65)
                {
                    txtFcs_grading.Text = "   C";
                }
                else if (totalsFcs >= 55)
                {
                    txtFcs_grading.Text = "   D";
                }
                else if (totalsFcs >= 45)
                {
                    txtFcs_grading.Text = "   E";
                }
                else
                {
                    txtFcs_grading.Text = "   F";
                }

            }
            catch (System.FormatException fmtE)
            {
                MessageBox.Show(fmtE.Message);
            }


        }

codes in class

C#

public object classworkfcs
       {
           get { return fcs_classwork; }
           set { fcs_classwork = Convert.ToDouble(value); }
       }

       public object iafcs
       {
           get { return fcs_ia; }
           set { fcs_ia = Convert.ToDouble(value); }
       }

       public object examsfcs
       {
           get { return fcs_exams; }
           set { fcs_exams = Convert.ToDouble(value); }
       }

       public object totalsfcs
       {
           get { return fcs_totals; }
           set { fcs_totals = Convert.ToDouble(value); }
       }
       public object gradingfcs
       {
           get { return fcs_grading; }
           set { fcs_grading = value.ToString(); }
       }

Posted 14-Jun-12 9:57am

mikeoabban

Updated 14-Jun-12 10:07am

Monjurul Habib

v2

Add a Solution

3 solutions

Solution 1

You did not say where you get the error? My guess is that something goes wrong here:

C#

classworkFcs = Convert.ToDouble(txtFcs_classwork.Text);
iaFcs = Convert.ToDouble(txtFcs_ia.Text);
examsFcs = Convert.ToDouble(txtFcs_exams.Text);

There is nothing wrong with the code here, but the data. For e.g.: if you classwork_txt is blank or someother string which can not be converted to double, you will get the error message which you currently get.
Option is to make sure that you get the correct data.

You can also try to use TryParse [^]method.

Posted 14-Jun-12 10:18am

Manas Bhardwaj

Comments

mikeoabban 14-Jun-12 16:23pm

the error comes when you click the save button.
in the sql2008 db i have this
fcs_classwork float,
fcs_ia float,
fcs_exams float,
fcs_totals float,
fcs_grading varchar (10),

could it be from here

Kschuler 14-Jun-12 17:10pm

You should be able to figure out exactly which line is causing the error. Put a breakpoint on the first line of code in the button's click event. Then step through the code one line at a time until you hit the error.

If you're a beginner and do not know about debugging, you could google for some tutorials. Here is a video I found that looks like it might help (it's for VB.net, but should provide you the basic concepts):
http://www.dailymotion.com/video/xd9sn0_visual-basic-visual-studio-tutorial_tech

mikeoabban 14-Jun-12 19:33pm

i just found out that it is from my clearscreen method. and this is the problem this.txtFcs_exams.Text = "";
when i comment it out, there is no error message displayed. i tried this
if (string.IsNullOrEmpty(this.txtFcs_classwork.Text) && string.IsNullOrEmpty(this.txtFcs_ia.Text))
{
txtFcs_exams.Text = "";
}
but did not work. please how do i clear the text in txtFcs_exams

Sergey Alexandrovich Kryukov 14-Jun-12 20:47pm

Makes sense, a 5.
--SA

Manas Bhardwaj 15-Jun-12 3:27am

thanx!

VJ Reddy 14-Jun-12 23:49pm

Good suggestion. 5!

Manas Bhardwaj 15-Jun-12 3:27am

thanx!

Solution 2

The .Text values type have to be same with Table or object datatype

C#

_with1 = person;
_with1.classworkfcs = txtFcs_classwork.Text;
                _with1.iafcs = txtFcs_ia.Text;
                _with1.examsfcs = txtFcs_exams.Text;
                _with1.totalsfcs = txtFcs_totals.Text;
                _with1.gradingfcs = txtFcs_grading.Text;

www.Tanvtech.com

Posted 14-Jun-12 10:20am

T.Ashraf

v2

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

mikeoabban · Accepted Answer · 2012-06-17T08:10:00

C#

//this is what i used. its that simple

 if ((!string.IsNullOrEmpty(txtFcs_classwork.Text)) && (!string.IsNullOrEmpty(txtFcs_ia.Text)) && (!string.IsNullOrEmpty(txtFcs_exams.Text)))
            {
                try
                {
txtFcs_totals.Text = (Convert.ToDouble(txtFcs_classwork.Text) + Convert.ToDouble(txtFcs_ia.Text) + Convert.ToDouble(txtFcs_exams.Text)).ToString();
                    double totalsFcs = Convert.ToDouble(txtFcs_totals.Text);

                    if (totalsFcs >= 75)
                    {
                        txtFcs_grading.Text = "   A";
                    }
                    else if (totalsFcs >= 70)
                    {
                        txtFcs_grading.Text = "   B";
                    }
                    else if (totalsFcs >= 65)
                    {
                        txtFcs_grading.Text = "   C";
                    }
                    else if (totalsFcs >= 55)
                    {
                        txtFcs_grading.Text = "   D";
                    }
                    else if (totalsFcs >= 45)
                    {
                        txtFcs_grading.Text = "   E";
                    }
                    else
                    {
                        txtFcs_grading.Text = "   F";
                    }



                }
                catch (System.FormatException fmtE)
                {
                    MessageBox.Show(fmtE.Message);
                }

            }