I have a webpage where I have a gridview. I have populated the gridview on page load event.
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
loadGridView();
}
}
This is the load gridview method.
private void loadGridView()
{
dataTable dt = getData(); // this function populates the data table fine.
gridView1.dataSource = dt;
gridview1.dataBind();
}
Now I have added linkButtons in one of the gridview columns in the RowDataBound event of the grid view.
protected void gvTicketStatus_RowDataBound(object sender, GridViewRowEventArgs e)
{
LinkButton lb = new LinkButton();
lb.Text = str1; // some text I am setting here
lb.ID = str2; // some text I am setting here
lb.Click += new EventHandler(lbStatus_click);
e.Row.Cells[3].Controls.Add(lb);
}
Finally This is the event Handler code for the link button click event.
private void lbStatus_click(object sender, EventArgs e)
{
string str = ((Control)sender).ID;
// next do something with this string
}
The problem is, the LinkButtons appear in the data grid fine, but the click event does not get execute. the control never reaches the event handler code. when I click the link button, the page simply gets refreshed. What could be the problem?
I have tried calling the loadGridView() method from outside the (!isPostBack) scope, but it did not help!
Try to work with the "Command" property instead of Click event
LinkButton lnkStatus = new LinkButton();
lnkStatus.ID = string.Format("lnkStatus_{0}", value);
lnkStatus.Text = "some text here";
lnkStatus.CommandArgument = "value";
lnkStatus.CommandName = "COMMANDNAME";
lnkStatus.Command += new CommandEventHandler(lnkStatus_Command);
Otherwise, if my proposal doesn't satisfy you, you have to remove the !Postback on Page_Load event.
you have to use OnRowCommand event of the GridView.
protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
{
if (e.CommandName.Equals("LinkButton1")) //call the CommandArgument name here.
{
//code
}
}
Related
I am trying to an add event handler to an image button in one of my view of multi view control. But the event handler is not firing. But if bind the buttons in page load then the event handler is firing. Can Anyone help?
LinkButton lnkButton = new LinkButton();
lnkButton.Click += new EventHandler(CButtonClickHandlerNew);
This is how I added the event handler.
Use the following code to call the event of dynamically created button
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)
{
placeHolder.Controls.Add(CreateButton());
}
}
public Button CreateButton()
{
Button btn = new Button();
btn.ID = "id";
btn.Text = "some text";
btn.Click += btn_Click;
return btn;
}
private void btn_Click(object sender, EventArgs e)
{
}
Whenever DropDownList SelectedIndexChanged, I am adding LinkButtons as ul-li list in codebehind. Each linkbuttons were assigned with IDs and a common Click event. Problem is code in Click event is not executed or maybe event is not triggered. My code below: [Edit] I tried like this as suggested in other posts (dynamically created list of link buttons, link buttons not posting back)
protected void ddl_SelectedIndexChanged(object sender, EventArgs e)
{
populate();
}
protected override void OnInit(EventArgs e)
{
base.OnInit(e);
populate();
}
void populate()
{
HtmlGenericControl ulList = new HtmlGenericControl("ul");
panel.Controls.Add(ulList);
foreach (DataRow dr in drc)
{
HtmlGenericControl liList = new HtmlGenericControl("li");
ulList.Controls.Add(liList);
var lnk = new LinkButton();
lnk.ID = dr["col1"].ToString();
lnk.Text = dr["col1"].ToString();
lnk.Click += Clicked;
liList.Controls.Add(lnk);
}
}
private void Clicked(object sender, EventArgs e)
{
var btn = (LinkButton)sender;
label1.Text = btn.ID.ToString();
}
Im missing something. Any help please.
Here the issue is with the ViewState. When the selected index of the dropdownlist changes there is a postback which takes place and the previous state is lost, so at this point you have to maintain the state of the controls.
Now in your code actually the state of the control is lost and so the click event does not fire. So the solution is to maintain the state of the controls.
The Below is a working example, you can just paste it and try.
This is my page load.
protected void Page_Load(object sender, EventArgs e)
{
for (var i = 0; i < LinkButtonNumber; i++)
AddLinkButton(i);
}
Similarly you have to maintain the state of the previously added control like this.
private int LinkButtonNumber
{
get
{
var number = ViewState["linkButtonNumber"];
return (number == null) ? 0 : (int)number;
}
set
{
ViewState["linkButtonNumber"] = value;
}
}
The below is my SelectedIndexChanged Event for the DropDownList
protected void Example_SelectedIndexChanged(object sender, EventArgs e)
{
AddLinkButton(LinkButtonNumber);
LinkButtonNumber++;
}
I have a function which dynamically creates the controls, which is called on the page load and on SelectedIndexChanged.
private void AddLinkButton(int index)
{
LinkButton linkbutton = new LinkButton { ID = string.Concat("txtDomain", index) };
linkbutton.ClientIDMode = ClientIDMode.Static;
linkbutton.Text = "Link Button ";
linkbutton.Click += linkbutton_Click;
PanelDomain.Controls.Add(linkbutton);
PanelDomain.Controls.Add(new LiteralControl("<br />"));
}
And this is the Click event for the LinkButton
void linkbutton_Click(object sender, EventArgs e)
{
//You logic here
}
I solved it using brute code lol.
Since controls' event were not bound on postback then we recreate them on postback. So in my Page_Load I called the module that re-creates the controls, thus binding them to corresponding event. This works, but...
Re-creating these controls create duplicates (Multiple Controls with same ID were found) and you will get into trouble in instances of finding a control by ID like using panel.FindControl.
To remedy this scenario, I put a check if same control ID already existed before recreating them, and voila! It works.
protected void Page_Load(object sender, EventArgs e)
{
populate();
}
void populate()
{
HtmlGenericControl ulList = new HtmlGenericControl("ul");
panel.Controls.Add(ulList);
foreach (DataRow dr in drc)
{
HtmlGenericControl liList = new HtmlGenericControl("li");
ulList.Controls.Add(liList);
if (liList.FindControl(dr["col1"].ToString()) == null)
{
var lnk = new LinkButton();
lnk.ID = dr["col1"].ToString();
lnk.Text = dr["col1"].ToString();
lnk.Click += Clicked;
liList.Controls.Add(lnk);
}
}
}
I have 1 gridview look like this:
Anytime user click on Bookmark button, I want to send the data in ProgramID column of that row to the List and pass it to second gridview in another page.But my second gridview doesn't display any data. What am I doing wrong?
This is my code for Bookmark button:
protected void btnSelect_Click(object sender, EventArgs e)
{
Button b = (Button)sender;
GridViewRow row = (GridViewRow)b.NamingContainer;
var ProgramID = row.FindControl("lblProgramID") as Label;
string stringProgramID = ProgramID.Text;
List<string> bookmarkPrograms = new List<string>();
bookmarkPrograms.Add(stringProgramID);
Session["BookmarkProgram"] = bookmarkPrograms;
}
And here is the code in Bookmark page:
protected void Page_Load(object sender, EventArgs e)
{
List<string> bookMarkPrograms = (List<string>)Session["BookMarkPrograms"];
GridView1.DataSource = bookMarkPrograms;
GridView1.DataBind();
}
I have some questions to this post [1]: How can i create dynamic button click event on dynamic button?
The solution is not working for me, I created dynamically an Button, which is inside in an asp:table controller.
I have try to save my dynamic elements in an Session, and allocate the Session value to the object in the Page_Load, but this is not working.
Some ideas
edit:
...
Button button = new Button();
button.ID = "BtnTag";
button.Text = "Tag generieren";
button.Click += button_TagGenerieren;
tabellenZelle.Controls.Add(button);
Session["table"] = table;
}
public void button_TagGenerieren(object sender, EventArgs e)
{
TableRowCollection tabellenZeilen = qvTabelle.Rows;
for (int i = 0; i < tabellenZeilen.Count; i++)
{
...
}
}
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
if (Session["table"] != null)
{
table = (Table) Session["table"];
Session["table"] = null;
}
}
}
It is not a good practice to store every control into Session state.
Only problem I found is you need to reload the controls with same Id, when the page is posted back to server. Otherwise, those controls will be null.
<asp:PlaceHolder runat="server" ID="PlaceHolder1" />
<asp:Label runat="server" ID="Label1"/>
protected void Page_Load(object sender, EventArgs e)
{
LoadControls();
}
private void LoadControls()
{
var button = new Button {ID = "BtnTag", Text = "Tag generieren"};
button.Click += button_Click;
PlaceHolder1.Controls.Add(button);
}
private void button_Click(object sender, EventArgs e)
{
Label1.Text = "BtnTag button is clicked";
}
Note: If you do not know the button's id (which is generated dynamically at run time), you want to save those ids in ViewState like this - https://stackoverflow.com/a/14449305/296861
The problem lies in the moment at which te button and it's event are created in the pagelifecycle. Try the page_init event for this.
Create Button in page load
Button btn = new Button();
btn.Text = "Dynamic";
btn.Click += new EventHandler(btnClick);
PlaceHolder1.Controls.Add(btn)
Button Click Event
protected void btnClick(object sender, EventArgs e)
{
// Coding to click event
}
I have a asp.net page with a datalist with a textbox and a button on it, on page load the textbox gets text in it, if I change the text and press the button the text doesn't get updated.
What am I doing wrong?
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DataTable table = CategoryAccess.GetProducts();
ProductList.DataSource = table;
ProductList.DataBind();
}
}
protected void btn_Click(object sender, EventArgs e)
{
string Name = textbox.Text;
CategoryAccess.UpdateProducts(Name);
}
}
I had same problem. I found that I put textbox.text = "xxx" in Page_Load() but outside if(!ispostback).
Try to add EnableViewState property in your textBox control and set the value to true.
e.g.
<asp:TextBox ID="textBox1"
EnableViewState="true"
MaxLength="25"
runat="server"/>
or you can do it programatically:
protected void Page_Load(object sender, EventArgs e)
{
textBox1.EnableViewState = true;
}
You need to bing again the new data...
protected void btn_Click(object sender, EventArgs e)
{
string Name = textbox.Text;
// you update with the new parametre
CategoryAccess.UpdateProducts(Name);
// you get the new data
DataTable table = CategoryAccess.GetProducts();
// and show it
ProductList.DataSource = table;
ProductList.DataBind();
}