I have a dropdownlist inside of a TemplateField, within a GridView.
I would like to dynamically add list items to it and write code to handle when the index changes. How do I go about manipulating the list, since I can't directly reference the DropDownList when it's in a TemplateField.
Here is my code:
<asp:TemplateField HeaderText="Transfer Location" Visible="false">
<EditItemTemplate>
<asp:DropDownList ID="ddlTransferLocation" runat="server" ></asp:DropDownList>
</EditItemTemplate>
</asp:TemplateField>
If I'm understanding what you want to do correctly, you can handle adding items to your drop down like this:
foreach (GridViewRow currentRow in gvMyGrid.Rows)
{
DropDownList myDropDown = (currentRow.FindControl("ddlTransferLocation") as DropDownList);
if (myDropDown != null)
{
myDropDown.Items.Add(new ListItem("some text", "a value"));
}
}
Then, if you mean handling the index change of the DropDownList you just need to add an event handler to your control:
<asp:DropDownList ID="ddlTransferLocation" runat="server" OnSelectedIndexChanged="ddlTransferLocation_SelectedIndexChanged" AutoPostBack="true"></asp:DropDownList>
Then in that event handler you can use (sender as DropDownList) to get whatever you need from it:
protected void ddlTransferLocation_SelectedIndexChanged(object sender, EventArgs e)
{
DropDownList myDropDown = (sender as DropDownList);
if (myDropDown != null) // do something
{
}
}
Related
I have a nested GridView(GvMP_Summary_Items). Each row contains a DropDownList. The DropDownList is bounded on the RowDataBound event of the nested GridView.
Each row also contains 1 Button. Upon pressing this button on the RowCommand event, I would like to find the current selected value of the DropDownList so I can use it further on in the code.
The code I have will only get the default value of the DropDownList on each row, which is currently set at 0 for each row.
Below is the RowCommand Event:
Protected Sub GvMP_Summary_Items_RowCommand(sender As Object, e As GridViewCommandEventArgs)
Dim lb As ImageButton = CType(e.CommandSource, ImageButton)
Dim gvRow As GridViewRow = lb.BindingContainer //Getting current row to get index
Dim GvMP_Summary_Items As GridView = CType(gvRow.FindControl("GvMP_Summary_Items"), GridView)
Dim intMPItem_Qty As Integer = CType(gvRow.FindControl("cboMPItem_Qty"), DropDownList).SelectedValue
Dim strMPItem_Qty As String = CType(gvRow.FindControl("txtMPItem_Qty"), TextBox).Text
End Sub
I have even included a TextBox in the GridView row which default value is empty "". Although on the row if something is entered the on RowCommand event brings back the value with a comma(,) in front of it.
This proves that I am picking up the correct row and can retrieve a value from a TextBox but not a DropDownList.
Is there something I am missing? Why can I return a value entered in a TextBox but not the selected value of a DropDownList? Also why the comma(,) in front of the TextBox value?
Note: In above case code has been written using VB so answers in VB over C# but I can accept both.
This can be done very easily by casting the CommandSource of the RowCommand back to a button and then get the correct row from that. Once you have the row you can use FindControl to locate the DropDownList. This works on every level of nested items and also on the top Control.
VB
Protected Sub GMP_Summary_Items_RowCommand(ByVal sender As Object, ByVal e As GridViewCommandEventArgs)
'cast the commandsource back to a button
Dim btn As Button = CType(e.CommandSource,Button)
'get the current gridviewrow from the button namingcontainer
Dim row As GridViewRow = CType(btn.NamingContainer,GridViewRow)
'use findcontrol to locate the dropdownlist in that row
Dim ddl As DropDownList = CType(row.FindControl("cboMPItem_Qty"),DropDownList)
'show the selected value of the dropdownlist
Label1.Text = ddl.SelectedValue
End Sub
Code was translated from C# with a code translator, so it may not be 100% accurate.
C#
protected void GMP_Summary_Items_RowCommand(object sender, GridViewCommandEventArgs e)
{
//cast the commandsource back to a button
Button btn = e.CommandSource as Button;
//get the current gridviewrow from the button namingcontainer
GridViewRow row = btn.NamingContainer as GridViewRow;
//use findcontrol to locate the dropdownlist in that row
DropDownList ddl = row.FindControl("cboMPItem_Qty") as DropDownList;
//show the selected value of the dropdownlist
Label1.Text = ddl.SelectedValue;
}
You do need to bind data to the GridView and the DropDownLists in an
IsPostBack check, otherwise the data will be rebound to the DDL on every PostBack and the selected value is lost
Important things:
Bind parent GridView in Page_Load method
Bind child GridView in parent GridView 's RowDataBound event
Bind DropDownList in child GridView 's RowDataBound event
Add CommandName to the Button which is inside child GridView
Finally, in RowCommand event of child GridView
Get child GridView 's row
Then find all controls inside child GridView from child GridView 's row
I'm not so aware of VB.NET so I have added an example (C#) of Nested GridView with RowCommand event (hope OP can use it in VB.NET):
HTML code (.Aspx):
<form id="form1" runat="server">
<asp:GridView ID="GridView_Outer" OnRowDataBound="GridView_Outer_RowDataBound" AutoGenerateColumns="false" runat="server">
<Columns>
<asp:TemplateField HeaderText="Outer Column1">
<ItemTemplate>
<asp:Label ID="Label_Outer" runat="server" Text='<%# Eval("Label_Outer") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Outer Column2">
<ItemTemplate>
<asp:GridView ID="GridView_Inner" OnRowDataBound="GridView_Inner_RowDataBound" OnRowCommand="GridView_Inner_RowCommand" AutoGenerateColumns="false" runat="server">
<Columns>
<asp:TemplateField HeaderText="Inner Column1">
<ItemTemplate>
<asp:Label ID="Label_Inner" runat="server" Text='<%# Eval("Label_Inner") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Inner Column2">
<ItemTemplate>
<asp:TextBox ID="TextBox_Inner" Text='<%# Eval("TextBox_Inner") %>' runat="server"></asp:TextBox>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Inner Column3">
<ItemTemplate>
<asp:DropDownList ID="DropDownList_Inner" runat="server"></asp:DropDownList>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Inner Column4">
<ItemTemplate>
<asp:Button ID="Button_Inner" runat="server" CommandName="BtnInnerCmd" Text="Inner Button" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
<br />
<asp:Label ID="Label_Result" runat="server"></asp:Label>
</form>
Code-Behind (.Aspx.cs):
DataTable TempDT = new DataTable();
protected void Page_Load(object sender, EventArgs e)
{
CreateDataTable();
if (!IsPostBack)
{
GridView_Outer.DataSource = TempDT;
GridView_Outer.DataBind();
}
}
// create DataTable
public void CreateDataTable()
{
TempDT = new DataTable();
TempDT.Columns.Add("Label_Outer");
TempDT.Columns.Add("Label_Inner");
TempDT.Columns.Add("TextBox_Inner");
TempDT.Rows.Add("OuterLabel", "InnerLabel", "");
TempDT.Rows.Add("OuterLabel", "InnerLabel", "");
// store DataTable into ViewState to prevent data loss on PostBack
ViewState["DT"] = TempDT;
}
// Calls Outer GridView on Data Binding
protected void GridView_Outer_RowDataBound(object sender, GridViewRowEventArgs e)
{
// check if gridview row is not in edit mode
if (e.Row.RowType == DataControlRowType.DataRow)
{
// Get Outer GrridView 's controls
Label Label_Outer = (Label)e.Row.FindControl("Label_Outer");
GridView GridView_Inner = (GridView)e.Row.FindControl("GridView_Inner");
// get DataTable from ViewState and set to Inner GridView
GridView_Inner.DataSource = (DataTable)ViewState["DT"];
GridView_Inner.DataBind();
}
}
// Calls Inner GridView on Data Binding
protected void GridView_Inner_RowDataBound(object sender, GridViewRowEventArgs e)
{
// check if gridview row is not in edit mode
if (e.Row.RowType == DataControlRowType.DataRow)
{
// Get Outer GrridView 's controls
DropDownList DropDownList_Inner = (DropDownList)e.Row.FindControl("DropDownList_Inner");
// Create a DataTable to Bind data for DropDownlist
DataTable TempDDLDT = new DataTable();
TempDDLDT.Columns.Add("ItemText");
TempDDLDT.Columns.Add("ItemValue");
TempDDLDT.Rows.Add("ItemText1", "ItemValue1");
TempDDLDT.Rows.Add("ItemText2", "ItemValue2");
// bind DataTable to the DropDownList
DropDownList_Inner.DataSource = TempDDLDT;
DropDownList_Inner.DataTextField = "ItemText";
DropDownList_Inner.DataValueField = "ItemValue";
DropDownList_Inner.DataBind();
}
}
// Calls when Inner GridView 's button clicked
protected void GridView_Inner_RowCommand(object sender, GridViewCommandEventArgs e)
{
// get Inner GridView 's clicked row
GridViewRow InnerGridViewRow = (GridViewRow)(((Control)e.CommandSource).NamingContainer);
// get Inner GridView 's controls from clicked row
TextBox TextBox_Inner = (TextBox)InnerGridViewRow.FindControl("TextBox_Inner");
DropDownList DropDownList_Inner = (DropDownList)InnerGridViewRow.FindControl("DropDownList_Inner");
// check if correct button is clicked
if (e.CommandName == "BtnInnerCmd")
{
string DropDownListValue = DropDownList_Inner.SelectedValue;
string TextBoxValue = TextBox_Inner.Text;
Label_Result.Text = "DropDownList 's Selected Value is " + DropDownListValue +
"<br />TextBox 's Entered Value is " + TextBoxValue;
}
}
Demo Image:
Note: Above DropDownList selects Selected Value not Text.
I have GridView filled automatically as
<asp:GridView ID="gvValues" runat="server"
OnRowDataBound="gvValues_RowDataBound"
OnPageIndexChanging="gvValues_PageIndexChanging"
<Columns>
<asp:TemplateField HeaderText="#">
<ItemTemplate>
<%# gvValues.PageSize*gvValues.PageIndex+ Container.DisplayIndex+1 %>
<asp:CheckBox ID="chkProduct" runat="server" CssClass="chkProduct"/>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="online" meta:resourcekey="Online">
<ItemTemplate >
<asp:CheckBox ID="chkProductonline" runat="server" OnCheckedChanged ="chkProductonline_CheckedChanged" AutoPostBack="true"/>
</ItemTemplate>
</asp:TemplateField>
What I need is when I click on the chkProductonline checkbox, to fire an event and get the chkProductonline and chkProducton values. I have tried this but it always gives me null.
protected void chkProductonline_CheckedChanged(object sender, EventArgs e)
{
var chkProductonline = FindControl("chkProductonline") as CheckBox;
// bool ischeck = chkProductonline.Checked;
var chkProduct = gvValues.FindControl("chkProduct") as CheckBox;
}
I can't loop the GridView. I need to do this one-by-one. Is there another way to do that?
You can try this:
protected void chkProductonline_CheckedChanged(object sender, EventArgs e)
{
CheckBox chkProductonline = sender as CheckBox;
...
CheckBox chkProduct = chkProductionLine.NamingContainer.FindControl("chkProduct") as CheckBox;
...
}
You need to call FindControl on a specific row. You will not be able to call it on the entire GridView because there exists repeating content (i.e. multiple chkProductionlines and chkProducts). A row knows of its checkboxes, and not of the others.
So what you can do is first get the CheckBox that called the event (your sender parameter, chkProductionline) and use its NamingContainer. Since it is contained in a GridView row, cast the row as such as use it to find the other controls you may need.
protected void chkProductonline_CheckedChanged(object sender, EventArgs e)
{
CheckBox chkProductionline = (CheckBox)sender;
GridViewRow row = (GridViewRow)chkProductionline.NamingContainer;
CheckBox chkProduct = (CheckBox)row.FindControl("chkProduct");
}
Within my EditTemplate I have a DropDownList as such:
<EditItemTemplate>
<asp:DropDownList ID="ddlFixture" runat="server" AutoPostBack="True" onselectedindexchanged="fixtureSelected"
DataSourceID="FixtureDataSource" DataTextField="WTag" DataValueField="WTag" AppendDataBoundItems="true" SelectedValue='<%#Bind("Fixure") %>'>
</asp:DropDownList>
</EditItemTemplate>
When the user selects an item from the DropDownList, I like to populate other fields in that are in EditMode as well.
You will notice that on onselectedindexchanged="fixtureSelected" I am calling fixtureSelected. I have noted some of the issues I am facing:
protected void fixtureSelected(object sender, EventArgs e)
{
// Below I am trying to get value of ddlFixture but it cannot recognize ddlFixture. GettingThe name 'ddlFixture' does not exist in the current context
string fixtureId = ddlFixture.SelectedItem.Value;
// I also need to update the text in EditMode but this will not work either. Get similar message as for ddlFixture
txtCampus.Text = "Campus1";
}
Your problem is due to the fact that the controls your are trying to access are inside the edititemtemplate of your GridView.
To get to the dropdownlist instance, you can use:
DropDownList ddlFixture = sender as DropDownList;
And to get the other controls in edititemtemplate, you use:
ddlFixture.NamingContainer.FindControl("control_id")
For example:
TextBox txtCampus = ddlFixture.NamingContainer.FindControl("txtCampus") as TextBox;
I am using a LinqDataSource and a FormView with paging enabled on an ASP.NET page. I am trying to access the FormView's DataItem property on PageLoad and I have no trouble on the first page load, but as soon as I use the Next/Prev page button (causing a postback) on the FormView the DataItem property is null, even if there a record showing in the FormView. Any ideas why it works fine on the first page load but not on a postback?
If you're curious what my PageLoad event looks like, here it is:
protected void Page_Load(object sender, EventArgs e)
{
Label lbl = (Label)fvData.FindControl("AREALabel");
if (fvData.DataItem != null && lbl != null)
{
INSTRUMENT_LOOP_DESCRIPTION record = (INSTRUMENT_LOOP_DESCRIPTION)fvData.DataItem;
var area = db.AREAs.SingleOrDefault(q => q.AREA1 == record.AREA);
if (area != null)
lbl.Text = area.AREA_NAME;
}
}
The object you bind to any data-bound control won't be persisted in the page's ViewState
Therefore, on subsequent posts the DataItem property will be null unless you re-bind the control
This property will contain a reference to the object when the control is bound.
Usually you would need to access this property if you want to do something when the objects is bound, so you need to react to the DataBound event
Example:
Output
Code behind
protected void ds_DataBound(object sender, EventArgs e)
{
var d = this.fv.DataItem as employee;
this.lbl.Text = d.lname;
}
ASPX
<asp:LinqDataSource ID="lds" runat="server"
ContextTypeName="DataClassesDataContext"
TableName="employees"
>
</asp:LinqDataSource>
<asp:FormView runat="server" ID="fv" DataSourceID="lds" AllowPaging="true"
OnDataBound="ds_DataBound">
<ItemTemplate>
<asp:TextBox Text='<%# Bind("fname") %>' runat="server" ID="txt" />
</ItemTemplate>
</asp:FormView>
<br />
<asp:Label ID="lbl" runat="server" />
Your data will not be preserved on PostBack. You'll need to rebind the FormView in the PageIndexChanging event using something like:
protected void FormView_PageIndexChanging(object sender, FormViewPageEventArgs e)
{
FormView.PageIndex = e.NewPageIndex;
//rebind your data here
}
In my application, when I edit a row in the gridview I choose some new data from a dropdownlist.
I am populating the dropdown like this:
protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
if ((e.Row.RowState & DataControlRowState.Edit) > 0)
{
DropDownList emailsListDL = (DropDownList)e.Row.FindControl("emailsDL");
emailsListDL.DataSource = allUsersEmails;//list of strings with the emails of the users
emailsListDL.DataBind();
}
}
}
But when I press the 'Update' button from the template and enters in the 'RowUpdating' event, the selected value from the dropdownlist is every time the first value from that dropdownlist.
protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
DropDownList emailsListDL = (DropDownList)GridViewAdvertisers.Rows[e.RowIndex].FindControl("emailsDL");
string email = emailsListDL.SelectedValue; //the selected value is every time the first value from the dropdownlist
}
Does anyone have any ideas?
I've tried many ways to set the selected value in the 'RowDataBound' event, but with no luck. I tried this:
1. emailsListDL.SelectedIndex = emailsListDL.Items.IndexOf(emailsListDL.Items.FindByValue(DataBinder.Eval(e.Row.DataItem, "OwnerMail").ToString()));
2. emailsListDL.SelectedValue = GridViewAdvertisers.DataKeys[e.Row.RowIndex]["OwnerMail"].ToString();
3. emailsListDL.SelectedValue = GridViewAdvertisers.Rows[e.Row.RowIndex].Cells[1].Text;
//ownerMail is a string (object) from the list of objects that I put as datasource to the gridview
Thanks,
Jeff
Update
My Item template from the aspx page is:
<asp:TemplateField ItemStyle-HorizontalAlign="Center" ItemStyle-VerticalAlign="Middle"
ItemStyle-Width="150px" HeaderText="Owner Email" HeaderStyle-HorizontalAlign="Left"
HeaderStyle-BorderWidth="1px" HeaderStyle-BorderColor="#e1e1e1">
<ItemTemplate>
<asp:Label ID="LabelEmail" runat="server" Text='<%# Bind("OwnerMail")%>'></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:DropDownList ID="emailsDL" runat="server" Width="150">
</asp:DropDownList>
</EditItemTemplate>
<HeaderStyle HorizontalAlign="Center" VerticalAlign="Middle" Font-Bold="True"></HeaderStyle>
<ItemStyle HorizontalAlign="Center" VerticalAlign="Middle" Width="180px" BorderWidth="1px"
BorderColor="#e1e1e1"></ItemStyle>
</asp:TemplateField>
The SelectedIndex will always default to 0 if you don't define it in your DropDownList definition.
Edit: #Tim Schmelter should add his comment as an anwer. In the meantime, I'll paraphrase for other readers: You need to check for postback (see comments above).
You can declare a ComboBox mainBX = new Combobox();
and you can declare an event
private void onSeletedIndexChange(object sender,EventArgs e)
{
mainBX = (ComboBox)(sender);
}
and next you should iterate foreach ComboBox in GridView and Add this Event .
Than all you should do is ,take the mainBX.seletedItem();
I think this is what you need ,if not apologise .
To set the Selected Value in the RowDataBound-Event, you should do it like this:
(DropDownList)e.Row.Cells[/*index*/].Controls[/*index, or use FindControl*/]).Items.FindByValue(((DataRowView)e.Row.DataItem).Row.ItemArray[/*columnnumber*/].ToString()).Selected = true;
FindByValue finds the current Textvalue of the Field in the "normal" Viewmode and sets the DropDownList with the value.
Of course this needs to be encapsulated in
if ((e.Row.RowState & DataControlRowState.Edit) == DataControlRowState.Edit)
{
}
As for your "getting the Value at Update"-Problem, I must honestly say I've got no clue, since your approach is exactly like mine, only difference: mine works.
Here's my code if it's any help:
protected void gridVariables_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
string control = ((DropDownList)gridVariables.Rows[e.RowIndex].Cells[3].Controls[1]).SelectedValue;
gridVariables.EditIndex = -1;
this.gridVariables_DataBind(control, e.RowIndex);
}
private void gridVariables_DataBind(string control, int index)
{
DataTable dt = (DataTable)Session["variableTable"]; //features a DataTable with the Contents of the Gridview
dt.Rows[index]["ControlType"] = control;
gridVariables.DataSource = dt;
gridVariables.DataBind();
}
I had the same problem with a different solution, I had implemented custom paging on the GridView with a custom pager, and in the process added the RowCommand method, which was rebinding the grid with a new page index. As it happens though the RowCommand method is also called during Updating.
So be sure to check any other locations you may be binding anywhere in your code.
Hope this helps somebody else.
protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
{
string commandName = e.CommandName;
switch (commandName)
{
case "Page1":
HandlePageCommand(e);
//binding should happen here
break;
}
//this line is in the wrong location, causing the bug
BindGrid1();
}