How to retrieve the first value displayed on the DevExpress' ASPxCombobox connecting to a SQL data source? After the page first loads, if I use selectedItem to retrieve the first value displayed on the ASPxCombo box without clicking on the combobox, I will get "null" for selectedItem. When I click and choose a value from a combobox, I can use selectedItem to get that value.
To access elements in dropdown window of ASPxComboBox use its Items collection:
//retrieve value of the first element in dropdown window of ASPxComboBox
var firstItem = comboBox.Items[0].Value
Combobox selecteditem would not be available on Page Load. Data isn't bound to control at this point, instead use DataBound event.
Webform1.aspx
<dx:ASPxComboBox ID="ASPxComboBox1" runat="server" DataSourceID="SqlDataSource2" TextField="CategoryName" ValueField="CategoryID">
</dx:ASPxComboBox>
<asp:SqlDataSource ID="SqlDataSource2" runat="server"
ConnectionString="<%$ ConnectionStrings:NWindConnectionString %>"
SelectCommand="SELECT * FROM [Categories]">
</asp:SqlDataSource>
Webform1.aspx.cs
void ASPxComboBox1_DataBound(object sender, EventArgs e)
{
ASPxComboBox1.SelectedIndex = 0;
object selectedItem = ASPxComboBox1.SelectedItem;
string selectedValue = ASPxComboBox1.SelectedItem.Value.ToString();
}
Write this in your Page_Load:
if (!IsPostBack)
{
cmb.DataBind();
cmb.SelectedIndex = 0;
}
If you want to get the first item in the combobox then use:
ASPxComboBox1.Items[0]
If you want to get the selected value then use:
ASPxComboBox1.Value
Related
this is for ticketing system where the tickets are in different status like 'open, rejected, closed, resolved..'
In asp.net i have a gridview and in the gridview there are textboxes and a dropdownlist.
i can get output from the database and get to populate it in the gridview and also the contents in the dropdown list are also displayed.
how can i get to bind the data of the dropdownlist in the grid to that of the output of the query. if the ticket is closed it should select closed, if the ticket is rejected it should select rejected.
in the onrowCommand, i fetch data from another table and populate into the dropdown list. this is the full list of status like 'oopen, rejected, closed, resolved..'
Your question is missing details like what markup you have used for gridview and also what code you have for RowDataBound event.
So, I have provided a sample answer that you can easily adapt to your situation.
I am assuming you have a gridview with an id of GridView1 that contains the following ItemTemplate ( other columns have been omitted since they are not needed to understand this approach).
You should have a hidden field in the template so you can store the current status of the row; also when you are binding your gridview you should be getting a column called Status for the row.
Sample Markup
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false"
OnRowDataBound="GridView1_OnRowDataBound">
<Columns>
<asp:TemplateField HeaderText = "Status">
<ItemTemplate>
<asp:HiddenField ID="hfStatus" runat="server" Value='<%# Eval("Status") %>' />
<asp:DropDownList ID="ddlStatus" runat="server">
</asp:DropDownList>
</ItemTemplate>
</asp:TemplateField>
</Columns>
Then in your RowDataBound event where you are binding the dropdown for the row, you need to get the value of hidden field hfStatus and then set the selected item of dropdown using this value.
I have assumed that a method called GetStatusDropDownListData is there that gets the data for binding dropdown list.
Sample RowDataBound event
protected void GridView1_OnRowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
//Find the DropDownList in the Row
DropDownList ddlStatus = (e.Row.FindControl("ddlStatus") as DropDownList);
ddlStatus.DataSource = GetStatusDropDownListData();
ddlStatus.DataTextField = "Status";
ddlStatus.DataValueField = "Status";
ddlStatus.DataBind();
//Select the Status in DropDownList
string currentStatus = (e.Row.FindControl("hfStatus") as HiddenField).Value;
ddlStatus.Items.FindByValue(currentStatus).Selected = true;
}
}
i had used this code and its working now:
in asp file:
' Visible = "false" />
in the .cs file
string currentStatus = (e.Row.FindControl("lblStatus") as Label).Text;
ddlStatus.Items.FindByValue(currentStatus).Selected = true;
I have SqlDataSource on my ASP.NET page and load this into Telerik's RadGrid control.
<asp:SqlDataSource
ID="DataSource"
runat="server"
ConnectionString="<%$ ConnectionStrings:ServerConnectionString %>"
SelectCommand="SELECT [Timestamp], [Label], [Project], [Product], [Value], [Reference] FROM [Operation]">
</asp:SqlDataSource
My field [Value] is a byte value representing an enum. When I load data into the grid I would like to convert these byte values into their enum equivalents, in other words I want clear text form.
I tried to do something in OnSelected and OnLoad() events of the SqlDataSource component but no success. Is there a way to access data in code behind coming from SqlDataSource before it is rendered?
You can look at the ItemDataBound event of the RadGrid which is similar to RowDataBound event in GridView. For example:
ASPX:
<telerik:RadGrid ID="RadGrid1" runat="server" DataSourceID="DataSource"
OnItemDataBound="RadGrid1_ItemDataBound" >
C# Code-Behind:
protected void RadGrid1_ItemDataBound(object sender, GridItemEventArgs e)
{
if (e.Item is GridDataItem) // get the row collection of cells/items
{
GridDataItem dataItem = (GridDataItem)e.Item;
// here we are converting the TEXT value to INT of the "VALUE" column
if(int.Parse(dataItem["Value"].Text) == 1)
dataItem["Value"].Text = "A"; // here you can set cell value as you like
}
}
I'm trying to populate a single text box (or parameter) with data from a gridview column when I click on a button in that row.
Gridview gets it data from a sqlconnection
the gridview is
| Drawing |
| 12345 | VIEW
| 12346 | VIEW
the VIEW is a template button with an onclick event, when the user clicks the button the data from the Drawing column (12345) should be passed to ether a textbox or a paremeter. (this is the part I dont know how to do) once the Iv got the number in a textbox I can use it as pareameter and then a pdf is opened of that drawing, I have code for this and is working.
thanks for any help
If you are using C#, the simplest thing to do would be to add an in-built select command button to the gridview rows at runtime. Then on the selectedindexchanged event of the gridview simply access the cell of the selected row that you want the value from. You can then assign that string to anything you want. Like so:
protected void myGridView_SelectedIndexChanged(object sender, EventArgs e)
{
string myString = myGridView.SelectedRow.Cells[4].Text.ToString();
TextBox1.Text = myString;
}
Remember that the cell index collection is zero based, so [0] is actually the first cell in the row.
Use TemplateFields and the grid view's OnRowCommand event, like this:
Markup:
<asp:gridview id="GridView1"
OnRowCommand="GridView1_RowCommand"
runat="server">
<Columns>
<asp:TemplateField>
<ItemTemplate>
<asp:TextBox ID="TextBoxDrawing" runat="server"
Text="<%# Eval("Drawing")) %>" />
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField>
<ItemTemplate>
<asp:Button ID="selc" runat="server" Text="View"
CommandName="View"
CommandArgument="<%# ((GridViewRow)Container).RowIndex %> />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
Code-behind:
protected void GridView1_RowCommand(Object sender, GridViewCommandEventArgs e)
{
// If multiple buttons are used in a GridView control, use the
// CommandName property to determine which button was clicked
if(e.CommandName == "View")
{
// Convert the row index stored in the CommandArgument
// property to an integer
var index = Convert.ToInt32(e.CommandArgument);
// Retrieve the row that contains the button clicked
// by the user from the Rows collection
var row = GridView1.Rows[index];
// Find the drawing value
var theDrawingTextBox = row.FindControl("TextBoxDrawing") as TextBox;
// Verify the text box exists before we try to use it
if(theDrawingTextBox != null)
{
var theDrawingValue = theDrawingTextBox.Text;
// Do something here with drawing value
}
}
}
I have inherited some code that has a GridView and a DetailsView in a webpart control.
The DetailsView is able to create two different kinds of an object e.g. TypeA and TypeB.
There's a dropdown list that filters the GridView by object type and the DetailsView has an automatically generated Insert button.
<asp:DetailsView ID="myDetailsView"
AutoGenerateInsertButton="True"
AutoGenerateEditButton="True"
AutoGenerateRows="false"
OnItemUpdating="OnItemUpdating"
DefaultMode="ReadOnly"
OnDataBound="OnDetailsViewBound"
OnItemInserting="OnItemInserting"
OnModeChanging="OnDetailsViewModeChanging"
runat="server">
I have been asked to:
remove the filter on the GridView; and
split the New buttons/links into two so there's a separate button for creating each type of object.
Removing the filter means that I need some other way to track what kind of object we're creating.
I have split the New links by changing the above to:
<asp:DetailsView ID="myDetailsView"
AutoGenerateInsertButton="False"
AutoGenerateEditButton="True"
AutoGenerateRows="false"
OnItemUpdating="OnItemUpdating"
DefaultMode="ReadOnly"
OnDataBound="OnDetailsViewBound"
OnItemInserting="OnItemInserting"
OnModeChanging="OnDetailsViewModeChanging"
runat="server">
and adding
<FooterTemplate>
<asp:TemplateField>
<ItemTemplate>
<asp:LinkButton runat="server" ID="lnkCreateNewTypeA" CommandName="New" CommandArgument="TypeA" CssClass="buttonlink">New Type A</asp:LinkButton>
<asp:LinkButton runat="server" ID="lnkCreateNewTypeB" CommandName="New" CommandArgument="TypeB" CssClass="buttonlink">New Type B</asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
</FooterTemplate>
I haven't yet removed the filter so the changes currently function the same as before, as I'm using the New command.
What I was hoping to be able to do is somehow capture the New event so I can put the CommandArgument value into a hidden field, that the DetailsView would then use to determine which type of object it's creating and also to show/hide fields.
When I put breakpoints in all of the event handlers in my code, the first one to break is OnDetailsViewModeChanging, which doesn't have access to the CommandArgument.
OnItemCommand (if it's hooked up) is triggered when any button within the DetailsView is pressed and does give me access to the CommandArgument but I'm not sure what exactly needs to be done within this method to mimic the chain of events that occurs when you use automatically generated buttons.
Is my only option for retrieving the CommandArgument to capture it in the OnItemCommand event handler or is there some other event that is triggered on the New command?
Can anyone explain to me the sequence of events that occurs when the New command is triggered?
I read somewhere that it changes the mode to Insert but I don't know what else it does. I believe the OnItemInserting method isn't called until the "Insert" link is clicked.
Any help would be gratefully received!!
Edit:
I have found this link on DetailsView events but it hasn't answered my question.
http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.detailsview_events.aspx
Edit:
I have tried adding the following:
in ascx:
<asp:DetailsView ID="myDetailsView"
...
OnItemCommand="OnItemCommand"
...
runat="server">
...
<asp:TemplateField HeaderText="Object Type" HeaderStyle-CssClass="columnHeader">
<ItemTemplate>
<asp:HiddenField runat="server" ID="hidObjectType" Value=""/>
<asp:Label runat="server" ID="lblObjectType"></asp:Label>
</ItemTemplate>
</asp:TemplateField>
in code behind:
protected void OnItemCommand(object sender, DetailsViewCommandEventArgs e)
{
if (e.CommandName.Equals("New"))
{
var objectType = e.CommandArgument.ToString();
HiddenField typeHidden = this.myDetailsView.FindControl("hidObjectType") as HiddenField;
if (typeHidden != null)
{
typeHidden.Value = objectType;
}
Label typeLabel = this.myDetailsView.FindControl("lblObjectType") as Label;
if (typeLabel != null)
{
typeLabel.Text = objectType;
}
}
}
I found that I didn't need to set the mode (this.myDetailsView.ChangeMode(DetailsViewMode.Insert);) in this method, as the OnDetailsViewModeChanging event handler still triggered.
This finds the controls and sets the values on them correctly. If I check the values again in OnDetailsViewModeChanging, their values are still set but as part of the logic in this method, there is a call to
this.myDetailsView.DataBind()
which causes a postback and at this point, the values are lost. I tried adding
EnableViewState="True"
but this made no difference. I've reviewed the page lifecycle (http://spazzarama.files.wordpress.com/2009/02/aspnet_page-control-life-cycle.pdf) and thought that maybe this.EnsureChildControls() would help but it's also made no difference.
An alternative would be to store the value in the session but I'd rather not.
As far as I can tell there is no event for capturing the "New" command aside from OnItemCommand, which captures all commands. (NOTE: You will need to make sure that CausesValidation="False" is set on your LinkButton or the code won't break into OnItemCommand).
When stepping through the code, the following occurred:
After the linkbutton was pressed, OnItemCommand is triggered. CommandName = "New" and here I could retrieve the CommandArgument
Next OnModeChanging is triggered. e.NewMode = "Insert". From all examples I've seen, here you call ChangeMode on the DetailsView and then call Databind() on it
Next OnDataBound is triggered as a result of calling Databind()
I didn't find a way to retain the value of the hidden variable between the various events so I ended up using a session variable. Code is below in case anyone wants it.
DetailsView declaration in the ASCX:
<asp:DetailsView ID="myDetailsView"
AutoGenerateInsertButton="False"
AutoGenerateEditButton="True"
AutoGenerateRows="false"
OnItemInserting="OnItemInserting"
OnItemUpdating="OnItemUpdating"
OnItemCommand="OnItemCommand"
DefaultMode="ReadOnly"
OnDataBound="OnDetailsViewBound"
OnModeChanging="OnDetailsViewModeChanging"
runat="server">
In the code-behind:
constant declarations...
private const string SESSIONKEY_MYVALUE = "MyValue";
private const string DEFAULT_OBJECTTYPE = "TypeA";
OnItemCommand event handler...
protected void OnItemCommand(object sender, DetailsViewCommandEventArgs e)
{
if (e.CommandName.Equals("New", StringComparison.InvariantCultureIgnoreCase))
{
var objectType = e.CommandArgument.ToString();
HiddenField typeHidden = this.myDetailsView.FindControl("hidObjectType") as HiddenField;
if (typeHidden != null)
{
typeHidden.Value = objectType;
}
HttpContext.Current.Session[SESSIONKEY_MYVALUE] = objectType;
}
}
OnModeChanging event handler....
protected void OnDetailsViewModeChanging(Object sender, DetailsViewModeEventArgs e)
{
if (e.NewMode == DetailsViewMode.Insert)
{
this.myDetailsView.ChangeMode(DetailsViewMode.Insert);
this.myDetailsView.DataBind();
}
}
OnDataBound event handler...
protected void OnDetailsViewBound(object sender, EventArgs e)
{
if (this.myDetailsView.CurrentMode == DetailsViewMode.Insert)
{
var sessionVar = HttpContext.Current.Session[SESSIONKEY_MYVALUE];
var objectType = sessionVar == null ?
DEFAULT_OBJECTTYPE :
sessionVar.ToString();
var typeHidden = this.myDetailsView.FindControl("hidObjectType") as HiddenField;
if (typeHidden != null)
{
typeHidden.Value = objectType;
}
}
}
In one of my form there were two Dropdown fields. The second dropdown has to be populated from the database, dynamically from the selection of first dropdown.
Any help is appreciated.
In the SelectedIndexChanged event of the first DropDownList, add code to populate the second DropDownList based on the selected value of the first list
Like this:
<asp:DropDownList runat="server" ID="from" AutoPostBack="true" CausesValidation="false" OnSelectedIndexChanged="from_SelectedIndexChanged">
</asp:DropDownList>
<asp:DropDownList runat="server" ID="to" />
protected void from_SelectedIndexChanged(object sender, EventArgs e)
{
var selectedValue = this.from.SelectedValue;
this.to.DataSource = /*get the data of the second list based on: selectedValue*/;
this.to.DataBind();
}