can't get value of selecteditem in DropDownList!!!!

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can't get value of selecteditem in DropDownList!!!!

Last post 07-10-2009 10:43 PM by MAW74656. 12 replies.

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can't get value of selecteditem in DropDownList!!!!

03-30-2005, 12:17 PM

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30 point Member
kristi3
Member since 02-09-2005, 11:48 AM
Posts 6

Hi:) I know this might sound simple, but I would like to use the selected item in my drop down list as the parameter in a query and then populate my text boxes with it! I can't see what I am doing wrong. Here is my code.. (the error that is thrown is telling me I can't convert string"" to double...)

Private Sub ddlInvNums2_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ddlInvNums2.SelectedIndexChanged

Dim selectedID As Integer

selectedID = ddlInvNums2.SelectedItem.Text

cmdType.Parameters("@invnum").Value = selectedID

MROcnn.Open()

Dim drea As SqlClient.SqlDataReader

drea = cmdType.ExecuteReader(CommandBehavior.SingleRow)

If drea.Read() Then

txttype.Text = drea(0)

End If

drea.Close()

MROcnn.Close

End Sub

help!

kristin Confused [*-)]

Re: can't get value of selecteditem in DropDownList!!!!

03-30-2005, 1:10 PM

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28,014 point All-Star
bmains
Member since 10-22-2004, 12:20 PM
Posts 5,651

You should check to see if the text is numeric, before passing it to the command and continuing. Do you have autopostback="true" on the dropdownlist? How are you populating the dropdownlist?

Brian

"Trust in the Lord and do what is good; dwell in the land and live securely. Take delight in the Lord, and He will give you your heart's desires" (Psalm 37: 3-4).

Re: can't get value of selecteditem in DropDownList!!!!

03-30-2005, 1:18 PM

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46,513 point All-Star
ndinakar
Member since 05-05-2003, 4:57 PM
Redmond, WA
Posts 6,858

(1) you need to declare the parameter first before you set its value.

here's a sample :

myCommand.Parameters.Add(New SqlParameter("@ttype",SqlDbType.VarChar,25))
myCommand.Parameters("@ttype").Value = "charge"

the first line above declares the parameter. the second line sets the value to it.

(2) I dont see your sql statemenr or the commandtype of stored procedure..

(3) IF you are requesting for only one value back from the database you can use Execute Scalar() Method which is much faster.

I'd recommend reading up some articles on Data Access.

***********************
Dinakar Nethi
Life is short. Enjoy it.
***********************

Re: can't get value of selecteditem in DropDownList!!!!

03-30-2005, 2:09 PM

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30 point Member
kristi3
Member since 02-09-2005, 11:48 AM
Posts 6

I have autopostback set to true. The error message is telling me that it isn't reading any value from the dropdownlist. what do you think?

kristin

Re: can't get value of selecteditem in DropDownList!!!!

03-30-2005, 2:18 PM

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30 point Member
kristi3
Member since 02-09-2005, 11:48 AM
Posts 6

the parameter is declared in the Collections as nvarchar . I am just wondering why it isn't reading the selecteditem.text.....

Re: can't get value of selecteditem in DropDownList!!!!

03-30-2005, 4:02 PM

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28,014 point All-Star
bmains
Member since 10-22-2004, 12:20 PM
Posts 5,651

Don't know, last time I had that problem was because I forgot to put if (not Page.IsPostBack) around my code loading the data into the page.

Brian

"Trust in the Lord and do what is good; dwell in the land and live securely. Take delight in the Lord, and He will give you your heart's desires" (Psalm 37: 3-4).

Re: can't get value of selecteditem in DropDownList!!!!

03-30-2005, 4:23 PM

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30 point Member
kristi3
Member since 02-09-2005, 11:48 AM
Posts 6

got that...still telling me input string not in the correct format.

InvalidCastException: Cast from string "" to type 'Double' is not valid.

Re: can't get value of selecteditem in DropDownList!!!!

03-31-2005, 7:42 AM

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stiletto
Member since 07-10-2003, 8:42 AM
Louisville, KY
Posts 3,216

Change:

selectedID = ddlInvNums2.SelectedItem.Text

To:

selectedID = Convert.ToInt32(ddlInvNums2.SelectedItem.Text)

Re: can't get value of selecteditem in DropDownList!!!!

03-31-2005, 9:37 AM

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30 point Member
kristi3
Member since 02-09-2005, 11:48 AM
Posts 6

nope Crying [:'(] still giving me that same error! For some reason it is reading the value of my dropdown as null! I'm ready to give up. but thanks for the input...

kristin

Re: can't get value of selecteditem in DropDownList!!!!

03-31-2005, 11:05 AM

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46,513 point All-Star
ndinakar
Member since 05-05-2003, 4:57 PM
Redmond, WA
Posts 6,858

you are probably losing the value during postback..do you have the If not ispostback loop in your page_load ?

***********************
Dinakar Nethi
Life is short. Enjoy it.
***********************

Re: can't get value of selecteditem in DropDownList!!!!

03-31-2005, 11:25 AM

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30 point Member
kristi3
Member since 02-09-2005, 11:48 AM
Posts 6

I have it. Do I have to have "if ispostback" in there?

I'm not sure if it matters, but the dropdownlist (ddlInvNumbers) is created dynamically. I fill it on page load like this:

If Not IsPostBack And txtinvnum.Text <> "" Then

Dim dreader As SqlClient.SqlDataReader

MROcnn.Open()

cmdAllNums.Parameters("@mrocomid").Value = txtinvnum.Text

dreader = cmdAllNums.ExecuteReader()

Dim firstrow As Boolean = True

While dreader.Read()

ddlInvNumbers.Items.Add(New ListItem(dreader(0).ToString()))

If firstrow Then

txtmrocomid.Text = dreader(1).ToString

txtinvnum.Text = dreader(1).ToString

txtnumber.Text = dreader(0).ToString()

txtcompany.Text = dreader(2).ToString()

txtbillingcontact.Text = dreader(3).ToString()

txtbillingphone.Text = dreader(4).ToString()

txtbillingext.Text = dreader(5).ToString()

txtbillingfax.Text = dreader(6).ToString()

txtbillingemail.Text = dreader(7).ToString()

txtbillingaddress.Text = dreader(8).ToString()

txtbillingaddress2.Text = dreader(9).ToString()

txtbillingcity.Text = dreader(10).ToString()

txtbillingstate.Text = dreader(11).ToString()

txtbillingzip.Text = dreader(12).ToString()

txtinvdate.Text = dreader(14).ToString()

txtinvdate.Text = FormatDateTime(txtinvdate.Text, DateFormat.ShortDate).ToString()

txttype.Text = dreader(15).ToString()

firstrow = False

End If

Session("MROID") = txtmrocomid.Text

End While

dreader.Close()

end if

what do you think?

Re: can't get value of selecteditem in DropDownList!!!!

04-01-2005, 9:49 PM

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stiletto
Member since 07-10-2003, 8:42 AM
Louisville, KY
Posts 3,216

You have to rebuild dynamic DDLs on every postback for the values to be there.

Re: can't get value of selecteditem in DropDownList!!!!

07-10-2009, 10:43 PM

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21 point Member
MAW74656
Member since 07-08-2009, 12:56 PM
Posts 26

Is this an ASP.NET DropDownList Control? If so, then ASP.NET creates a new id for the control when it is rendered for the browser. See This Post for help finding the client id.

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