How do you access a control after postback with __EVENTTARGET in asp.net 2.0 and not get "object reference not set to an instance of an object" Error. Because when I try access a objects property I get that error
View 2 RepliesI'm making a site and throughout the site I haven't been very consistent with the way I get user input on postbacks. For example, say in a button event that takes two strings retrieved from textboxes and adds them together and outputs the string sum in a label:
protected void btnCalculate_Click(object sender, EventArgs e)
{
string text1 = textBox1.Text; //one way
string text2 = Request["textBox2"]; //the other way
lblSum.Text = text1+text2;
}
I imagine you would want to use Request[""] if the data has been posted to a new page, but for this situation, is one way preferred over another, and why?
I need to access the controls dynamically created template fields at run time in datagrid in post back event. Is there any way to retrieve the values in post back event? Or else give the ideas to acheive my requirement. I need to create no of rows and columns as text box as per user input. After fill the values to text box , i need to access the values in submit button.
View 1 Repliesiam using the Jquery Uframe with asp.net project.Iam getting a postback problem here.
In side the uframe ,button control getting postback the page even the client side method call also.
i tried with the Html button Control also by setting the type="submit" ,iam facing the same problem.
And I got very limited reference about the uframe(codeflex,codeProject).
On postback, how can I check which control cause postback in Page_Init event.
protected void Page_Init(object sender, EventArgs e)
{
//need to check here which control cause postback?
}
if (Page.IsPostBack)
{
//here I need to know which control causes the postback
}
I have a radgrid controlling access to an application for users. There are two columns, a 'name' column and a checkbox 'access' column representing their current access permission. the checkboxes are populated from a database. I would like the to change the checkboxes to grant or deny access to the users I specify. Since there are alot of users I would like to make multiple changes and use a submit button to write the changes to the database. I do not want to postback with each checkbox change and wait for the page to "blink". My problem is that with the checkbox postback disabled, when I click submit, the value of the checkboxes are not registering the changes I make. I need a way to access the current client-side state of the checkbox or some workaround to accomplish this.
View 5 Replieshow do I access variables in a simple asp.net postback using either POST or GET?
View 2 RepliesMy problem is:
I've got a table, dynamically created, fill with a lot of dropdownlists witches IDs are dynamically created.
When a button is pressed, I need to scan all controls in the table and save their value.
But after the postback I can't no longer access to the table.
I have a script which creates a dynamic textbox (and more) in an AJAX async post back. But when I try to acess the textbox I am told "Object reference not set to an instance of an object". I have been strugleing with this for a long time. This is written in C# .Net 4. The line causing the problem is the very last one where I have tbGameName.Text.Trim()
[Code]....
I am using two listbox for moving items from one to another using jquery. Auto postback is set to false for both the listboxes. Is there a way to access the items server side on postback?
View 3 RepliesWhen I click the button to open the modal popup it shows the popup but then continues and forces a postback causing the page to reload and the modal popup to be hidden again.Here is the markup for the control:
<asp:Button id="LoginOpenButton" runat="server" Text="Login"/>
<asp:Panel ID="ContentPanel" runat="server" CssClass="modalPopup">
<fieldset> [code]....
My script manager has no properties other than the id and runat set.
In my default.aspx page I have a PlaceHolder control within an UpdatePanel. In this placeholder control I will dynamically load a web user control, which is just a form with a submit button. On this user control, I have the form within an update panel and I have the "Submit" button's Click Event added to the triggers.
When I submit the form, the UpdatePanel on the web user control nor the update panel on the default.aspx page are capturing the post back, thus causing a full post back which refreshes my page.
how to capture this post so its rendered in Ajax and not a full post back?
Im wondering how to get a label control that is in a header template in a datalist on an aspx page. I need the control text to change when the user checks a checkbox outside of the list on the page somewhere. I tried Itemdatabound, but I dont want to have to rebind the list everytime the user checks the box (lots of slow reaction time)
View 1 RepliesI had a little project is create dynamic control. My project had get detail of content and replace in sign string, Add control in sign. After click button I will find in control, I had added on page load in panel. I can't get value in child control panel, Don't have control in panel. My source is
protected void Page_Load(object sender, EventArgs e)
{
string config_design = GetConfigueKey(configDesign);
Genform(config_design, GetContent(config_design));
if (IsPostBack)
{
btn_submit_click(sender, e);
}
else
{
string config_design = GetConfigueKey(configDesign);
Genform(config_design, GetContent(config_design));
}
}
protected String GetContent(string designname)
{
string rev = "";
mClsDB = new clsConn();
strSql = "SELECT STR_DESIGN_CONTENT,STR_DESIGN_NAME,INT_FORM_ID FROM TBL_DESIGN WHERE INT_DESIGN_ID = " + designname + " ";
DataTable dt = mClsDB.GetDataTable(strSql);
if (dt != null)
{
if (dt.Rows.Count > 0)
{
rev = dt.Rows[0]["STR_DESIGN_CONTENT"].ToString();
}
}
return rev;
}
protected void Genform(string designname, string content)
{
string rev = content;
mClsDB = new clsConn();
//strSQL = " SELECT INT_FIELD_ID,STR_FIELD_NAME,STR_FIELD_SIZE,STR_FIELD_CSS,STR_FIELD_DEFAULTVALUE,BIT_FIELD_VISIBLE,INT_FIELD_VALIDATE_TYPE,STR_FIELD_MINMAX,STR_FIELD_TYPE_NAME ";..................
I have a page with an panel on it that can contain a number of editable controls (textboxes, date pickers etc). This panel (and the controls) are populated dynamicaly by loading up an XSLT tranformation and applying it to an XML document (which represents the entity being edited) in the Pages Load event if !isPostBack.
Once the user has made changes they click a button and the form posts back. At that point I want to be able to go through the various controls in the panel, get the updated values and persist them back to a database. When I try to access the controls in the underlying buttons even theyre not there the panel is empty.
What I think is happening is that the page is being recreated at the start of the post back. When its recreated the XSLT transformation doesnt run because its a postback so the edit panel never gets repopulated. The controls therefore dont exist as far as my Button handler is concerned and it cant access their values.
My stopgap solution to this is that Im not checking isPostBack before repopulating the panel, so now the panel gets repopulated in the post back, the controls are there and Im able to query their values. The problem is that this involves another round trip to the database server to pick up the xslt and thats undesirable.So, first of all, have I understood the problem correctly?
I could save the trip to the db by storing the xslt (probably in the view state) but the whole idea of having to load up the control before checking its values feels sort of wrong and Im concerned that Im doing the wrong thing without realising. When I repopulate the control I am, of course, applying the XSLT to the XML document as it stood before the user made any edits. I would have expected querying the value of a control to return me the value before the user changes, but it actually seems to return me the value of the control as it was in the page when the user clicked the button. How can that be?
I need to create dynamic radio buttons in my page, and then access their values in postback
I create the buttons using the following code:
[Code]....
In the post back I try to access the radio buttons using their created ID:
[Code]....
But it seems that the find method is never finding the Radio button control.
I have several checkbox controls on my web form that are not server controls (runat="server") How can I access these controls form my C# code? Can this be done with document.GetelementById from the server side using C#? Or some other technique?
I am not allowed to make these server controls (runat=server) because of a requirement.
I have several usercontrols which are loaded based on business logic.However, all of them have webcontrols whose selected/entered value needs to be accessible in parent page on an event.Since there can be any combination of UserControls, I do not want to load all the UserControls in the Parent Page, since they are heavy.
I would like to load only those controls which are supposed to appear on the page, yet access the value from the usercontrol which caused the postback. (I would rather not access using Request.Form) (ViewState is open, but unsuccessful to store value in parent page's viewstate in onClick)Here is a sample scenario
Page: Home
Dynamically Loads: UserControls1
UserControls has TextBox tb and Button btn, causing onClick
When btn is clicked, I want to get value of tb in parent page on PostBack, Page creates UserControl2
I m a begginer in asp.net. I hav connected the ms-access 2003 wit asp.net 2005 using vb. I can view the data by usin this code.
Dim msaccessconnect, query, databasecommunication, readdatabase
msaccessconnect = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;data source=" & Server.MapPath("db1.mdb"))
msaccessconnect.Open()
query = "SELECT * FROM `advertiser`"
databasecommunication = New OleDbCommand(query, msaccessconnect)
readdatabase = databasecommunication.ExecuteReader()
GridView1.DataSource = readdatabase
GridView1.DataBind()
readdatabase.Close()
msaccessconnect.Close()
But I dont know to update, delete options in tat.
I have used calender web user control inside my project where i took textbox,button and calender...but after dragging onto my aspx page..i am unable to access this textbox,calender and button on aspx page..
View 5 RepliesI have a wizard control and I have defined a custom header template for it and I have put a label control inside that header template and I need to access it programaticly at runtime.
How do I get reference to it in the 'ActiveStepChanged' event of the wiard?
I need to access a control inside a repeater and change its properties. To enable it or not. I got an erorr message Object reference not set to an instance of an object. Here is my code inside a method. protected void
rptCAP_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
LinkButton lnDel = (LinkButton)rptCap.FindControl("lnkDelete");
lnkDel.Enabled = false; //<<<<< this is where the error occur
}
The name of the repeater control is id="rptCAP"
MSDN documentation says that the ScriptManager class is part of the System.Web.UI namespace and I see that I can create a ScriptManager object programmatically. However, I don't see the ScriptManager control on the front-end. Do I need to reference the Ajax Control Toolkit dll in order to have access to control?
View 6 RepliesI have a calendar control in which i am loading data from db using the below method.
[code]...
What i want to achieve is in the selection changed event of the calendar.I would like to access the calendar selected cell value.I tried to look for a event in the selection changed method but unable to come up with any.Let me know if anyone came across this and able to access the value in the selected cell control value.