Length cannot be less than zero. Parameter name: length

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protected void btn_Logout_Click1(object sender, EventArgs e)
    {
        string tempval = urlval;
        int strval = tempval.Length;
        string logoutstring = tempval.Substring(0, strval - 31);
        Response.Redirect(logoutstring);

    }

getting error in the above code....someone please help me.....
Length cannot be less than zero. Parameter name: length

Posted 3-Jun-10 3:03am

avijit1112009

Updated 3-Jun-10 3:08am

PSK_

v2

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4 solutions

Solution 4

check strval length as
if(tempval.Length=>31)
{
string logoutstring = tempval.Substring(0, strval - 31);
}
else
{

// write your code whatever you want
}

hope it will help you

Posted 3-Jun-10 6:27am

Lalit Kumar 5733

Comments

Sandeep Mewara 3-Jun-10 13:11pm

Reason for my vote of 1
Whats different from other responses here?

Solution 3

I'm guessing that strval - 31 is less than zero.

Posted 3-Jun-10 3:09am

R. Giskard Reventlov

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#realJSOP · Accepted Answer · 2010-06-03T03:07:00

well, the problem is that strval is probably less than 31. A quick fix would be to do this:

string logoutstring = tempval.Substring(0, Math.Max(0, strval - 31));

That way, the ssecond parameter will always be at least 0.

EDIT ---------

I don't get it. I actually provided code to fix the problem, and my response is voted lower?

GregWyatt · Accepted Answer · 2010-06-03T03:06:00

Solution 1

The substring functions work by starting at an index and then returning the next X characters.

So, Substring(0, strval-31) is telling it to start at index 0 and travel strval-31 places. strval-31 is the length that it will travel so when you minus 31 from strval it is less than 0 which is not valid.

Posted 3-Jun-10 3:06am

GregWyatt

Updated 3-Jun-10 3:49am

v3