input string is not in a correct format c#

Question

I want to multiply the text value and combo box value and display it in a orderprice textbox the data types that I use in sql are 'float' for all of these

private void cb_oqty_SelectedIndexChanged(object sender, EventArgs e)
{
    int orderprice;
    int proprice=Convert.ToInt16(txt_oprice.Text);
    int quantity = Convert.ToInt16(cb_oqty.SelectedItem);

    orderprice = proprice * quantity;
    txt_orderprice.Text = Convert.ToString(orderprice);
    txt_orderprice.Update();                                
}

You need to put breakpoints and debug individual line. Only that way you can find out which statement is throwing the exception. — Yahya
– Yahya, Commented Mar 8, 2016 at 10:36
I think when combo fill all items that particular time it throws exception. it comes before selecting combo value or after selecting? — Faraz Ahmed
– Faraz Ahmed, Commented Mar 8, 2016 at 10:38
i am getting error on this line int proprice=Convert.ToInt16(txt_oprice.Text); — Ali Goreja
– Ali Goreja, Commented Mar 8, 2016 at 10:43
@AlyGoreja it comes after selecting combo value or before? where you give data to combo box?? i.e in form load? — Faraz Ahmed
– Faraz Ahmed, Commented Mar 8, 2016 at 10:50
when i select value from combo box after it and it does not show the value tgrows an exception — Ali Goreja
– Ali Goreja, Commented Mar 8, 2016 at 10:50

James Dev · Accepted Answer · 2016-03-08 10:51:35Z

1

Use int.TryParse to see if the text can be converted first. That error seems to point to text not being able to be converted to int.

int orderprice = 0;
int proprice = 0;
int quantity = 0;

if (int.TryParse(txt_oprice.Text, out proprice) && int.TryParse(cb_oqty.SelectedValue.ToString(), out quantity))
{
    // It was assigned.
    orderprice = proprice * quantity;
}
else
{
    //Error
}

Also the cb_oqty.SelectedItem will not convert to an int as it is an Object. you need to use SelectedValue.

edited Mar 8, 2016 at 10:51

answered Mar 8, 2016 at 10:38

James Dev

3,0191 gold badge13 silver badges17 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

Ali Goreja Over a year ago

it is giving error at int.tryparse(cb_oqty.selectedvalue, out quantity)

James Dev Over a year ago

int.TryParse(cb_oqty.SelectedValue.ToString(), out quantity). It needs to be SelectedValue.ToString()

Ali Goreja Over a year ago

error object rerference not set to be an instance of an object at tryparse line

Ali Goreja Over a year ago

and after i select value from combo box

James Dev Over a year ago

Put a break point on the if statement. View in the debugger watch what the combo box values have.

|

nvoigt · Accepted Answer · 2016-03-08 10:42:06Z

0

If your SQL datattype is float, your C# datatype should be float as well:

    private void cb_oqty_SelectedIndexChanged(object sender, EventArgs e)
    {
        var proprice = Convert.ToSingle(txt_oprice.Text);
        var quantity = Convert.ToSingle(cb_oqty.SelectedItem);

        var orderprice = proprice * quantity;
        txt_orderprice.Text = orderprice.ToString();

        // this does not do what you think it does. You can remove this line.
        txt_orderprice.Update();
    }

Better would be using the TryParse method.

answered Mar 8, 2016 at 10:42

nvoigt

77.8k28 gold badges103 silver badges156 bronze badges

Collectives™ on Stack Overflow

input string is not in a correct format c#

2 Answers 2

7 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

7 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related