I have a LinqDataSource that I use to calculate the number of rows in a table. I would like to update the value of literal with the number, with the following code, taken from MSDN (linqdatasourcestatuseventargs.totalrowcount.aspx):
protected void linqDataSource1_Selected(object sender, LinqDataSourceStatusEventArgs e)
{
Literal1.Text = e.TotalRowCount.ToString();
}
By how do I trigger the select event on the data source? The SqlDataSource class has a Select() method so that it can be triggered programmatically in e.g. Page_Load, but the LinqDataSource does not have this method. I currently solved the problem by binding my data source to an empty FormView element, but this is just too ugly.
I feel pretty confident that there is a much nicer way to get the total number of rows into my literal when using LinqToSql, I just don't know how to do so.
The suggestion by tvanfosson, of attaching an method to the data source's selected event, does unfortunately not solve my problem, because the select event is still not triggered when the page loads. (I have, by the way, already attached the _Selected method with the OnSelected attribute, like this)
<asp:LinqDataSource ID="linqDataSource1" runat="server"
OnSelected="linqDataSource1_Selected">
Hook up your method as an event handler for the Selected event in Page_Load.
public void Page_Load( object sender, EventArgs e )
{
linqDataSource1.Selected += LinqDataSource1_Selected;
}
protected void LinqDataSource1_Selected(object sender, LinqDataSourceStatusEventArgs e)
{
Literal1.Text = e.TotalRowCount.ToString();
}
I ended up dropping the data source and instead put the code in the code behind. Not really the point-and-click-programming that I was going for, but still quite short. I looks something like this:
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
var context = new MyDataContext();
numberOfModificationsLiteral.Text =
(
from modification in context.Modifications
where modification.Start >= DateTime.Now
select modification
).Count().ToString();
}
}
Related
Can anyone help me on this?
I have a button(ImageButton1) inside a GridView (gvSdt), and gridview b is inside another Gridview (gvClass).
but it come out an error said "The name 'gvSdt' does not exist in the current context"
The code i used as below:
protected void gvSdt_SelectedIndexChanged(object sender, EventArgs e)
{
GridViewRow row = gvSdt.SelectedRow;
int rowIndex = gvSdt.SelectedIndex;
string strValue = gvSdt.DataKeys[rowIndex].Value.ToString();
}
Since gvSdt is contained within another GridView, you won't be able to access it directly, as it is repeated content. Since gvSdt can exist multiple times, gvSdt would therefore refer to multiple GridViews.
This is made easy however, since you are using the SelectedIndexChanged event of the GridView in question. Notice the sender argument of the method. The object that gets passed there is actually the GridView. So just cast it as such.
protected void gvSdt_SelectedIndexChanged(object sender, EventArgs e)
{
GridView gvSdt = (GridView)sender;
GridViewRow row = gvSdt.SelectedRow;
int rowIndex = gvSdt.SelectedIndex;
string strValue = gvSdt.DataKeys[rowIndex].Value.ToString();
}
I know I must be missing something simple but I cannot find it so I will pose the question here. I have a formview with two templates (item and edititem).
The form is bound to the itemtemplate in the page_Load event and works fine. However, if is use !IsPostBack in the code-behind, the formview disappears when the edit button is clicked. If I remove the postback check from page_load, then the form view appears after the edit button is clicked.
The page does have viewstate enabled.
In general, what steps are needed to get the formview to transition between modes correctly?
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
source = Session["Source"].ToString();
acctType = Session["AccountType"].ToString();
acctNumber = Convert.ToInt32(Session["AccountNumber"]);
if (source == "LifeLineDS")
{
ObjectDataSource fvObjDS = new ObjectDataSource();
fvObjDS.TypeName = "LifelineDataAccess.LifelineSubscriber";
fvObjDS.SelectMethod = "GetLifelineDSSubscriber";
fvObjDS.SelectParameters.Add(new Parameter("AcctType", TypeCode.String, acctType));
fvObjDS.SelectParameters.Add(new Parameter("AcctNumber", TypeCode.String, Session["AccountNumber"].ToString()));
fvObjDS.DataBind();
if (fvObjDS != null)
{
fvSubscriber.DataSource = fvObjDS; //subscriber.ToString();
fvSubscriber.DataBind();
initialProgramValue = (fvSubscriber.FindControl("txtEligibility") as TextBox).Text;
}
}
// more code for other sources...
}
protected void btnEdit_Click(object sender, EventArgs e)
{
fvSubscriber.ChangeMode(FormViewMode.Edit);
fvSubscriber.DataSource = Session["subscriber"]; //Adding this line resolved !IsPostBack problem
fvSubscriber.DataBind();
ObjectDataSource programsObjDS = new ObjectDataSource();
programsObjDS.TypeName = "LifelineDataAccess.LifelineSubscriber";
programsObjDS.SelectMethod = "GetPrograms";
DropDownList ddlEligibility = ((DropDownList)(fvSubscriber.FindControl("ddlEligibility")));
if (ddlEligibility != null)
{
ddlEligibility.DataSource = programsObjDS;
ddlEligibility.DataTextField = "ProgramName";
ddlEligibility.DataValueField = "ProgramName";
ddlEligibility.SelectedValue = initialProgramValue; // Set selected value to subscribers current program
ddlEligibility.DataBind();
}
}
This
fvSubscriber.ChangeMode(FormViewMode.Edit);
fvSubscriber.DataBind();
seems to not to set the data source. The rule is that either you have the DataSourceID set in the declarative part of your code (*.aspx, *.ascx) and the binding is done automatically upon each postback OR you bind programmatically which involves setting the data source and calling the DataBind().
My recommendation would be to move your ObjectDataSource to the declarative part of the code and set the DataSourceID on the FormView to the ID of the ObjectDataSource. This is clean and easy and the binding works always.
I want to edit row of gridview.For that, I have added showeditbutton = true.I have binded gridview from cs file.Does I need to wite 3 function for that?(For editing I have added 3 function in cs file.).I have taken help from internet.But some point did not understand.
--In aspx
<asp:GridView datakeyname="Id" Id ="Gridview1" onRowEditing="GridView1_RowEditing" RowCancelingEdit=" GridView1_RowCancelingEdit" onRowUpdating ="GridView1_RowUpdating" >
<column>
// hyperlink ,dataTextfield is id
// some checkboxfield.(start from column 6)
</column>
protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
{
GridView1.EditIndex = e.NewEditIndex;
//code for Binding grid
}
protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
// for fetching value of id and checkboxfield(column 6)
string Id= GridView1.DataKeys[e.RowIndex].Values["Id"].ToString());
bool ischeck = (Gridview1.Rows[e.RowIndex].Cells[5].Controls[0] as checkBox).Checked;
// code for updating grid
GridView1.EditIndex = -1;
//Now bind the gridview gain here
}
protected void GridView1_RowCancelingEdit(object sender, GridViewUpdateEventArgs e)
{
GridView1.EditIndex = -1;
//Now bind the gridview gain here
}
Does am I going in right direction?What is use of datakey.Does I used properly?Why GridView1.EditIndex = -1 in update and cancel event.Column 6 is checkboxfield.why .Controls[0] is used for accessing that checkboxfield.
If you are using an ObjectDataSource (or SqlDataSource or OleDbDataSource) to databind and use UpdateCommand, DeleteCommand, InsertCommand, then you do not need to explicitly write those three functions for the edit/update operation. You need those functions when you are writing the binding code in code-behind or if you want to do additional work before/after any operation.
RowEditing fires when you click "edit" on the GridView. Here you specify what row to open in editmode by writing GridView1.EditIndex = e.NewEditIndex. You can also write code here to do any work that is required before user is put into editmode. For example, you can check for business rules conditions, and cancel the operation if rules are not met.
RowUpdating fires when you click "save"/"update" on the GridView. This is fired before the actual database operation. If you have an UpdateCommand on the datasource, then you do not need to write database save routine, otherwise you write that here.
DataKeys identify the "key" that identifies the data that is bound. You specify DataKeys while databinding to the GridView. For example, primary key of a database table. This line: string Id= GridView1.DataKeys[e.RowIndex].Values["Id"].ToString()); Here you are picking up the value of the "Id" key (you can have more than one keys) of the current row.
GridView1.EditIndex = -1 in update or cancel specifies that the GridView should no longer be in editmode. If this value is >= 0, then the GridView is put into editmode for that row (index starting from 0). So we set it to -1, to indicate that it should not be in editmode.
Controls[0] is used to pick the first control in that cell (you may have more than one controls). Alternatively, you can also use FindControl.
http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.gridview.sorting.aspx
This article deals with creating a datatable first, then creating a gridview from it, to aid in sorting. My predicament is slightly different.
I have a Gridview, that on Page_Load, I set the datasource to an ArrayList, and bind.
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
this.GridView1.DataSource = RequestManager.Instance.GetAllRequests();
this.GridView1.DataBind();
}
}
Now I would like to sort this GridView, so on the aspx page, I set AllowSorting="true", and OnSorting="GridView1_Sorting". So far, so good. I have the SortExpressions set in the BoundFields, and when I click on it, I know the _Sorting event is triggered.
Now, since this is a postback operation, I cannot simply cast the datasource of the gridview to a DataTable to sort. Saving to ViewState is an option, but I cannot figure out how to do it.
I would like to use the simple solution on this page, except for the DataTable not being available to me. Thanks for looking.
If you're able to target .NET v3.5, I recommend using Linq. In your _Sorting event handler, get the array list you did in the Page_Load and rebind it.
For example, if the type contained in the array list are MyType instances that have properties named Default and SomeField:
protected void Grid_Sorting(object sender, GridViewSortEventArgs e)
{
Func<MyType, object> keySelector;
if(e.SortExpresion == "SomeField")
{
keySelector = dataItem => dataItem.SomeField;
}
else
{
keySelector = dataItem => dataItem.Default;
}
ArrayList dataItems = RequestManager.Instance.GetAllRequests();
this.GridView1.DataSource = dataItems.OfType<MyType>().OrderBy(keySelector);
this.GridView1.DataBind();
}
That will get you started, then later inspect the sort expression to see if it ends with ASC or DESC and conditionally call .OrderByDescending(keySelector).
Finally, I don't recommend stashing the list in ViewState, as the ObjectStateFormatter is only optimized for a handful of types. http://msdn.microsoft.com/en-us/library/system.web.ui.objectstateformatter.aspx
Maybe consider ASP.NET cache instead.
I have a GridView that gets it's data from the SQL database.
I would like to alter some of it using an external method, something like this:
SQL in:
ID:0
Then, the altered method will be called with 0 as a parameter, and will return some string that will be shows in the GridView.
Thank you, Mark.
Attach a handler to the RowDataBound event. You have full control to all of the cells in the GridViewRow, and can modify the text anyway you want. Example from MSDN:
void CustomersGridView_RowDataBound(Object sender, GridViewRowEventArgs e)
{
if(e.Row.RowType == DataControlRowType.DataRow)
{
// Display the company name in italics.
e.Row.Cells[1].Text = "<i>" + e.Row.Cells[1].Text + "</i>";
}
}
Reference at: http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.gridview.rowdatabound.aspx