In celldouble click event "Input string was not in a correct format." error is generated..

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C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace ass3cs
{
    public partial class show_database : Form
    {
        public show_database()
        {
            InitializeComponent();
        }
        
        private void show_database_Load(object sender, EventArgs e)
        {
            SqlConnection dbconnection = new SqlConnection("Data Source=.\\SQLEXPRESS;AttachDbFilename=E:\\edu\\7th sem\\a.net\\assignment\\ass3cs\\ass3cs\\BikeData.mdf;Integrated Security=True;User Instance=True");
            dbconnection.Open();
            
            SqlDataAdapter sda = new SqlDataAdapter("SELECT * FROM customer_database", dbconnection);

            DataTable dt = new DataTable();
            sda.Fill(dt);
            GridView.DataSource = dt;
        }

        private void close_btn_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void GridView_CellDoubleClick(object sender, DataGridViewCellEventArgs e)
        {
            Int id = Convert.ToInt32(GridView.Rows[e.RowIndex].Cells[0].Value);
            UpdateDatabase ud = new UpdateDatabase(id);
            ud.ShowDialog();
        }       
    }
}

Posted 11-Oct-12 9:10am

NishTrivedi

Updated 11-Oct-12 9:18am

v3

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Comments

[no name] 11-Oct-12 15:17pm

And the value of the string when the error is generated is what? Use Int32.Parse or TryParse instead of Convert.

NishTrivedi 11-Oct-12 16:04pm

Input string is not in correct format.
and sorry..
TryParse does not work.

[no name] 11-Oct-12 16:11pm

"does not work" is not very helpful in describing a problem. TryParse does work. And "Input string is not in correct format" is not an answer. What is the value of the string that you are trying to convert?

NishTrivedi 11-Oct-12 16:15pm

i want to get the cell number while i click on that cell.
and i want to convert string value into integer value.

[no name] 11-Oct-12 16:18pm

Believe it or not I understand that already. What is the string that you are trying to convert? It's a simple question...

NishTrivedi 11-Oct-12 16:20pm

string contains name value.

[no name] 11-Oct-12 16:22pm

And what exactly does that mean? You mean a string containing a name like "Bob"?

NishTrivedi 11-Oct-12 16:17pm

when i use TryParse at that time "No overload for method 'TryParse' takes 1 argument is generate.

[no name] 11-Oct-12 16:19pm

And? So you did not use the function properly. That does not mean the function does not work. That means that you did not use it correctly.

NishTrivedi 11-Oct-12 16:22pm

Int id = Convert.ToInt32(GridView.Rows[e.RowIndex].Cells[0].Value);

so can you tell me how i use TryParse in this code line??

[no name] 11-Oct-12 16:28pm

Yes, although I fail to see why you cannot read the documentation yourself.
int t;
Int32.TryParse(GridView.Rows[e.RowIndex].Cells[0].Value, out t);

NishTrivedi 11-Oct-12 16:56pm

Argument 1: cannot convert from 'object' to 'string' error generate.

[no name] 11-Oct-12 17:02pm

Then try
Int32.TryParse(GridView.Rows[e.RowIndex].Cells[0].Value.ToString(), out t);

NishTrivedi 11-Oct-12 17:08pm

exception:conversion failed when converting the varchar value 'xyz' to datatype int.

NishTrivedi 11-Oct-12 17:11pm

http://mindstick.com/Articles/924bee57-80b0-4ec7-8cdb-24207ed8d7e9/

i want to perform this task.

[no name] 11-Oct-12 17:12pm

And? Did you expect something else? Do you think that "xyz" should be an int somehow?

[no name] 11-Oct-12 17:17pm

And that is an exception from your database.

NishTrivedi 12-Oct-12 8:58am

yes

ridoy 11-Oct-12 15:51pm

try with int id..in place of Int

NishTrivedi 11-Oct-12 16:05pm

no change..
still same error is generate.

3 solutions

Solution 1

If you are going to use the Convert.ToInt32 method then you need to wrap that call in a try-catch so that you can capture and deal with that exception.
The better and more preferred ways would be to use the Int32.Parse or TryParse methods as Wes has alluded to in his comment.

The basic concept to learn here is that all user input should be treated as though it is evil. Validate the hell out of it and make sure that you can catch as many eventualities as you can and deal with them appropriately.

[Update]: The reasons for the exception to occur in the Convert.ToInt32 scenario are plenty. If the textbox value is empty or if the textbox value contains anything other than just 0 through 9 then this exception will occur. The idea of the try catch is to provide a graceful handling of the error.

C#

int valueToUse;
try
{
   valueToUse = Convert.ToInt32(GridView.Rows[e.RowIndex].Cells[0].Value);
   // I suspect that you may want to use .Text instead of .Value here
   // valueToUse = Convert.ToInt32(GridView.Rows[e.RowIndex].Cells[0].Text);
}
catch( Excetion error )
{
   // Set a default value so that you can go on.
   valueToUse = 0;
}

The preferred way would be to use the TryParse though.

C#

int valueToUse;
// TryParse returns a boolean indicating whether the conversion was successful.
if( !Int32.TryParse( GridView.Rows[e.RowIndex].Cells[0].Value, out valueToUse ) )
{
   // Set a default value.
   valueToUse = 0;

  // Notify the user or do whatever else you want.
}

Posted 11-Oct-12 9:43am

fjdiewornncalwe

Updated 11-Oct-12 10:41am

v3

Comments

NishTrivedi 11-Oct-12 15:53pm

hi Marcus,
still the same error is generated using convet.toint32 in try-catch..

fjdiewornncalwe 11-Oct-12 16:35pm

Of course the error will still occur because the input in the textbox cannot be converted into a number. The try-catch will just give you the opportunity of applying a default value or letting the user know in a graceful way.

NishTrivedi 11-Oct-12 16:54pm

Argument 1: cannot convert from 'object' to 'string'
error generate.

fjdiewornncalwe 11-Oct-12 16:56pm

Show the 1 line of code, please?

NishTrivedi 11-Oct-12 16:57pm

this line creates the error:
GridView.Rows[e.RowIndex].Cells[0].Value

fjdiewornncalwe 11-Oct-12 17:08pm

Try GridView.Rows[e.RowIndex].Cells[0].Value.ToString() or GridView.Rows[e.RowIndex].Cells[0].Text

NishTrivedi 11-Oct-12 17:10pm

exception message:conversion failed when converting the varchar value 'xyz' to datatype int.

fjdiewornncalwe 11-Oct-12 17:15pm

Do you not see the problem there? Of course "xyz" won't convert to an int.

NishTrivedi 11-Oct-12 17:11pm

http://mindstick.com/Articles/924bee57-80b0-4ec7-8cdb-24207ed8d7e9/

i want to perform this task..

Solution 2

See these..you may find answer..
http://social.msdn.microsoft.com/Forums/en/csharpgeneral/thread/d0c45c47-7f17-4fb1-8228-ac2b6750db58[^]
http://msdn.microsoft.com/en-us/library/system.windows.forms.datagridview.celldoubleclick%28v=vs.85%29.aspx[^]

Posted 11-Oct-12 10:22am

ridoy

Comments

NishTrivedi 12-Oct-12 12:33pm

it is not helpful for me.

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NishTrivedi · Accepted Answer · 2012-10-13T22:35:00

Solution 3

C#

private void GridView_CellDoubleClick(object sender, DataGridViewCellEventArgs e)
       {
           UpdateDatabase ud = new UpdateDatabase();
           ud.Controls["Fname_tbox"].Text = GridView.CurrentRow.Cells[0].Value.ToString();
           ud.Show();

       }

Posted 13-Oct-12 22:35pm

NishTrivedi