This code give me error( System.NullReferenceException: Object reference not set to an instance of an object.)

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C#

private void ReadTextBoxes()
{
    string strValue = string.Empty;
    int n = NumberOfControls;
    Panel pnl = (Panel)Page.FindControl("Panel1");

    for (int i = 0; i <= NumberOfControls; i++)
    {
        //:confused: This line Give me error please give me solution
        string boxName = "TextBoxID" + (i + 1).ToString();


        TextBox tb = pnl.FindControl(boxName) as TextBox;
        strValue += tb.Text + "\n";

    }
    Response.Write(strValue);

}

Posted 8-Mar-10 18:30pm

preetirinku

Updated 8-Mar-10 19:02pm

Sandeep Mewara

v2

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Sandeep Mewara · Answer 1 · 2010-03-08T19:21:00

Either you are getting Panel Object value as null or textbox Object value as null.

REASON 1:
Error line must be:
strValue += tb.Text + "\n";

Issue1 to me looks at:

strValue += tb.Text + "\n";

Looks like you are getting "null" for tb value here:

TextBox tb = pnl.FindControl(boxName) as TextBox;

Reason:

string boxName = "TextBoxID" + (i + 1).ToString();

REASON 2:
Error line must be:
TextBox tb = pnl.FindControl(boxName) as TextBox;

If pnl value is null, then this line would throw an error.

Issue2 to me looks at:

TextBox tb = pnl.FindControl(boxName) as TextBox;

Looks like you are getting "null" for pnl value here:

Panel pnl = (Panel)Page.FindControl("Panel1");

Check that you have "Panel1" named Panel with you.

===========
I don't think you must be getting error at the location specified by you.

string boxName = "TextBoxID" + (i + 1).ToString();

There is nothing wrong with this statement.