Develop Reference

C# Code-behind control form execution

I have a form that I would like to reuse for both adding a new record and editing an existing record. I am able to successfully load the page with the relevant data when I select a record from a GridView and I am able to update the db record appropriately. However, my issue is trying to use the form for both executions. Here is my logic in code behind: (I assign a session variable when I click on the row in GridView and this does work successfully)
protected void Page_Load(object sender, EventArgs e)
{
resultOutput.Visible = false;//Output results as to whether or not a record was added successfully is automatically hidden at page load
//Checking to see if session variable has been created
if (Session["editID"] != null)
{
//Create objects to get recipe data
dbCRUD db = new dbCRUD();
Recipe editRecipe = new Recipe();
//Grabbing session ID and assigning to a variable in order to remove the session variable
var id = Convert.ToInt32(Session["editID"]);
Session.Remove("editID");
//Call method to retrieve db data
editRecipe = db.SelectRecord(id);
//Populate results to text boxes
recordID.Text = id.ToString();
addName.Text = editRecipe.Name;
addTypeDDL.SelectedValue = editRecipe.Meal;
addDifficultyDDL.SelectedValue = editRecipe.Difficulty;
addCookTime.Text = editRecipe.Cook_Time.ToString();
addDirections.Text = editRecipe.Directions;
//Change Button Text
submitRecord.Visible = false;
changeRecord.Visible = true;
//Change Title Text
addEditTitle.Text = "Edit Recipe";
}
}
protected void submitRecord_Click(object sender, EventArgs e)
{
//Variables for execution results
var modified = "";
int returned = 0;
//Creating the recipe Object to pull the values from the form and
//send the recipe object as a parameter to the method containing insert stored procedure
//depending on Add or Edit
Recipe recipe = new Recipe();
recipe.Name = addName.Text;
recipe.Meal = addTypeDDL.Text;
recipe.Difficulty = addDifficultyDDL.Text;
recipe.Cook_Time = int.Parse(addCookTime.Text);
recipe.Directions = addDirections.Text;
//Creating object to access insert method
dbCRUD newRecord = new dbCRUD();
//Checking to see if the page is loaded for edit or new addition
if (Session["editID"] != null)
{
//If recordID exists, recipe will be passed as to UpdateRecord method
recipe.Recipe_ID = int.Parse(recordID.Text);
returned = newRecord.UpdateRecord(recipe);
modified = "has been edited.";
Session.Remove("editID");
}
else
{
//If recordID does not exist, record will be passed to InsertRecord method (new recipe)
returned = newRecord.InsertRecord(recipe);
modified = "added";
}
//Method returns 0 if successful, 1 if sql error, 2 if other error
if (returned == 1)
{
resultOutput.Text = "There was an sql exception";
resultOutput.Visible = true;
}
else if (returned == 2)
{
resultOutput.Text = "There was a non sql exception";
resultOutput.Visible = true;
}
else
{
resultOutput.Text = "\"" + addName.Text + "\" recipe " + modified;
resultOutput.Visible = true;
}
}
I have issues on the if(Session["editID"] != null) line - I am always moved to the else logic and the if logic never runs.
Here is my click method in the GridView:
protected void Grid_Recipe_SelectedIndexChanged(object sender, EventArgs e)
{
int index = Convert.ToInt32(Grid_Recipe.SelectedDataKey.Value);
Session["editID"] = index;
Response.Redirect("addRecord.aspx");
}
My question is how can I control execution during the submitRecord_Click event so that I call the appropriate method. Thanks!

Have you considered using
if(Page.IsPostBack)
{
code here
}
To detect whether you are posting back to the page? Then you could check your value of the item. I see no reason the code shouldn't be in the Session variable - have you tried putting a breakpoint in there to see if the code actually gets in there?
Also does your addRecord.aspx just add the record? If so, just add the record in this class, but use the PostBack check to see. Could you just make sure you are saving in the right context aswell:
// Outside of Web Forms page class, use HttpContext.Current.
HttpContext context = HttpContext.Current;
context.Session["editID"] = index;
...
int Id = (string)(context.Session["editID"]);

I was able to figure out my issue - which actually turned into two issues. First, I had to put my Page Load logic in a if(!IsPostBack) statement because I could not edit the page. Reason being is I was loading the originally posted data to the form on page load, which executed before my logic. Adding the if(!IsPostBack) control statement fixed this issue. From there, I'm still using a session variable to control code behind logic, only I made sure keep my session variable only between the form and the gridview. Basically, when the gridview loads and it is not a post back, the session variable is cleared. This let's me set a new session variable when I click on a row and then the session variable is cleared once I return to the grid to see the results. Thanks for the help!

Cannot find instance of dynamically added UserControl .Net

I have a UserControl which I am loading into a div which is inside an UpdatePanel. Here is my code for loading it:
controls.IDLControl IdlControl = LoadControl(#"~/controls/IDLControl.ascx") as controls.IDLControl;
IdlControl.ClientIDMode = ClientIDMode.Static;
IdlControl.ID = "IDLControl";
spGroup.Controls.Clear();
spGroup.Controls.Add(IdlControl);
And here is my code for trying to retrieve an instance of it:
controls.IDLControl IdlControl = RecursiveFindControl(this, "IDLControl") as controls.IDLControl;
private Control RecursiveFindControl(Control targetControl, string findControlId) {
if (targetControl.HasControls()) {
foreach (Control childControl in targetControl.Controls) {
if (childControl.ID == findControlId) {
return childControl;
}
RecursiveFindControl(childControl, findControlId);
}
}
return null;
}
But, all I get is null. I need help on figuring this out.
AFAIK, I need to re-add the control to the page on pre-init but it is one of the controls that can be added depending on which option is selected from a drop down list (which also is filled dynamically). I am stuck trying to figure out how to make this work.

You can try something like this to add your control back in the Page_Init based on the option selected in your DropDownList.
protected void Page_Init(Object sender, EventArgs e)
{
if (IsPostBack)
{
if (drpYourDropDown.Items.Count > 0 && drpYourDropDown.SelectedItem.Text == "yourOption")
{
AddIDLControl();
}
}
}
private void AddIDLControl()
{
controls.IDLControl IdlControl = LoadControl(#"~/controls/IDLControl.ascx") as controls.IDLControl;
IdlControl.ClientIDMode = ClientIDMode.Static;
IdlControl.ID = "IDLControl";
spGroup.Controls.Clear();
spGroup.Controls.Add(IdlControl);
}

Property or indexer '' cannot be assigned to -- it is read only

I have a class that is a list of class objects.
[Serializable]
public class UserRequestOrders
{
private List<RTORequestOrder> m_thisUsersOrders = new List<RTORequestOrder>();
public List<RTORequestOrder> RequestOrders
{
get { return m_thisUsersOrders; }
set { m_thisUsersOrders = value; }
}
}
When I create an instance of this object I need to populate the list variable When m_thisUsersOrders with an existing list of requests (from a viewstate).
MyOrders.RequestOrders = (List<RTODataEntryObjects.RTORequestOrder>)ViewState["vsMyOrders"];
When the page posts back, I cast the viewstate into a list of RTORequestOrder objects, and try to set the RequestOrders property, I get the message that the property or indexer cannot be assigned to. I have a "SET" accessor for the property.
All posts that I have read on this topic state that I need to modify scope in the application settings, but I am not sure how that applies here. I don't have any application settings set.
I am hoping someone can help me understand how I can populate the list from an existing list.
EDIT: Nico, Thanks for your response! Below is the full code from the code behind page. "MyOrders" and "lst" are essentially the same thing. When I am working with "lst" everything works the way that I want it to. The reason that I want to use the "MyOrders" object instead is because I have a method that returns the list as a datatable with only the fields I need to display. (I didnt' show that code because the issue appears to be with the "SET" accessor.) "lst" has the same signiture as the "MyOrders.RequestOrders". Why can I cast the the viewstate into the lst object, but not the MyOrders object?
EDIT: Grant, thanks for your response as well. I don't know how to set breakpoints for ASP pages... :(
public partial class Default3 : System.Web.UI.Page
{
RTODataEntryObjects.UserRequestOrders MyOrders = new RTODataEntryObjects.UserRequestOrders();
List<RTODataEntryObjects.RTORequestOrder> lst = new List<RTODataEntryObjects.RTORequestOrder>();
void Page_PreRender(object sender, EventArgs e)
{
if (ViewState["vsMyOrders"] == null)
{
NewDataGrid.DataSource = (RTODataEntryObjects.UserRequestOrders)ViewState["vsMyOrders"]; // code to show the data in the grid when page loading
}
}
protected void Page_Load(object sender, EventArgs e)
{
NewDataGrid.EnableViewState = true;
NewDataGrid.DataSource = (RTODataEntryObjects.UserRequestOrders)ViewState["vsMyOrders"];
NewDataGrid.DataBind();
}
public void btnSubmit(object sender, EventArgs e)
{
int id = Int32.Parse(TextBox1.Text); // dynamically getting the data from the frontend.
string name = TextBox2.Text; // dynamically getting the data from the frontend.
if (ViewState["vsMyOrders"] != null) // if the view state is already having data then can update the list and assign again to the viewstate later.
{
lst = (List<RTODataEntryObjects.RTORequestOrder>)ViewState["vsMyOrders"];
MyOrders.RequestOrders = (List<RTODataEntryObjects.RTORequestOrder>)ViewState["vsMyOrders"];
}
RTODataEntryObjects.RTORequestOrder thisOrder = new RTODataEntryObjects.RTORequestOrder(id, name, User.Identity.Name, System.Environment.MachineName);
lst.Add(thisOrder); //
MyOrders.AddNew(thisOrder);
ViewState["vsMyOrders"] = MyOrders;
NewDataGrid.DataSource = (IList<RTODataEntryObjects.RTORequestOrder>)ViewState["vsMyOrders"];
NewDataGrid.DataBind();
}
}

Trying to update a record, but the update code only updates one of the timestamp fields and nothing else

I have a database table that I need to update records on. The code to add a new record works just fine, But when I go to update an existing record, not all the fields update with the new information in the form.
Here's the code:
private void updateExistingDSN()
{
//Update existing DSN
try
{
using (PathFinderDataContext pfdcContext = new PathFinderDataContext())
{
DSN oldDSN = pfdcContext.DSNs.Single(dsn => dsn.DSNID == int.Parse(Request["dsn"]));
oldDSN.Auth_AuthorizationID = int.Parse(Request["auth"]);
oldDSN.ServiceProvided_ServiceProvidedID = int.Parse(Request["sp"]);
oldDSN.EvidenceBPMU = short.Parse(ddlEvidenceBPMU.SelectedValue);
oldDSN.LocationOfVisit = txtLocationOfVisit.Text;
oldDSN.ChildrenPresent = txtNamesOfChildrenPresent.Text;
oldDSN.ParentPresent = txtNamesOfParentsPresent.Text;
oldDSN.OthersPresent = txtNamesOfOthersPresent.Text;
oldDSN.DescribeGoals = txtDescribeGoals.Text;
oldDSN.DescribeStrategy = txtDescribeStrategies.Text;
oldDSN.DescibeParentingSkills = txtDescribeParentingSkills.Text;
oldDSN.DescribeSafetyConcerns = txtDescribeSafetyConcerns.Text;
oldDSN.OtherInfo = txtOtherInfo.Text;
oldDSN.Schedule_Monday = float.Parse(txtMonday.Text);
oldDSN.Schedule_Tuesday = float.Parse(txtTuesday.Text);
oldDSN.Schedule_Wednesday = float.Parse(txtWednesday.Text);
oldDSN.Schedule_Thursday = float.Parse(txtThursday.Text);
oldDSN.Schedule_Friday = float.Parse(txtFriday.Text);
oldDSN.Schedule_Saturday = float.Parse(txtSaturday.Text);
oldDSN.Schedule_Sunday = float.Parse(txtSunday.Text);
oldDSN.DateSaved = DateTime.Now;
oldDSN.SavedBy_UserID = currentEmployee.EmployeeID;
pfdcContext.SubmitChanges();
}
Response.Redirect("~/pages/updateTimesheet.aspx?action=update&ProvidedServiceId=" + int.Parse(Request["sp"]));
}
catch (Exception ex)
{
errorMessage.Text = "<b>Error updating an existing DSN record!</b><br /><br />" + ex.ToString();
warnings.Visible = true;
}
}
The only field that updates is oldDSN.DateSaved, everything else just stays the same. No errors or exceptions thrown or anything. Acts like it works, but doesn't. Also, when I hardcode values to be updated, the record updates just fine. Any ideas?

In your Page_Load (where you put the information from your datasource into the TextBoxes, etc) you need to wrap the databinding code in a If(Page.IsPostBack) block.
So your code should look something like this:
protected void Page_Load (object sender, EventArgs e)
{
if(!Page.IsPostBack)
{
// Whatever you use to load the data from the database into
// your server controls goes here
loadData(); // example
}
}
This is why you're not getting the updated information - your markup elements are being reloaded from the database before your Update code has a chance to run.

Which is the recommended way to fill all controls on a Web Form when user selects a record?

I have a GridView control which shows a list of all employees. When user selects any employee from this list, the record is shown on a Web Form with all input controls pre-filled with the values.
I want to know any good approach to do this. Should I bind all input controls to any SqlDataSource or should I re-populate all input controls by picking values from the DataSet.

First you add the select button on your GridView as:
<asp:ButtonField Text="Select" CommandName="ViewMe" ButtonType="Button" />
then you add the OnRowCommand="RowCommand" property on GridView to call this function when the button is clicked and on code behind the function:
protected void RowCommand(object sender, GridViewCommandEventArgs e)
{
// if the ViewMe command is fired
if (e.CommandName == "ViewMe")
{
// go to find the index on the grid view
int iTheIndexNow;
if (int.TryParse(e.CommandArgument.ToString(), out iTheIndexNow))
{
// Set and highlight the selected
TheGridView.SelectedIndex = iTheIndexNow;
// do we have the table data id ?
if (TheGridView.SelectedValue != null)
{
// now load the controls data using this id
LoadValuesFromDatabaseToControls(TheGridView.SelectedValue);
}
}
}
}
I prefer this way of command button because you can add more commands than the select, or edit, even the delete or copy... the just index change can be done for any reason (eg by changing page) and is also need again the select.
I use the subsonic 2 DAL for loading the data from the database. A sample code from my programs is:
void LoadValuesFromDatabaseToControls(string editID)
{
// Load it from database
AthUserMaiListName OneRow = new AthUserMaiListName(editID);
if (OneRow.IsNotExist)
{
// a custom control that show messages on top.
uResult.addMsg("Fail to load id " + editID, MsgType.error);
// close the view of the controls
dbViewPanel.Visible = false;
}
else // else we have the data and go for show them
{
// show this panel that contains the controls.
dbViewPanel.Visible = true;
// I keep my current edit id
lblID.Text = editID;
// just be sure that the select exist on DrowDownList
MyUtils.SelectDropDownList(ddlEventType, OneRow.CAddedFrom);
txtEmail.Text = OneRow.CEmail;
txtFirstName.Text = OneRow.CFirstName;
txtLastName.Text = OneRow.CLastName;
txtInsideTitle.Text = OneRow.CInsideTitle;
txtCompanyName.Text = OneRow.CCompanyName;
txtCreated.Text = DateTimeRender(OneRow.CreatedOn);
txtModified.Text = DateTimeRender(OneRow.ModifiedOn);
}
}

I used this code in my application-
A better approach would call to this mothod on gridview_select_index_change() event
private void PickValues(int SerialNum)
{
DataSet ds = new DataSet();
try
{
string Query = "SELECT * FROM tw_main WHERE sno = " + SerialNum;
ds = reuse.ReturnDataSet(Query, "Scheme");
//Add Scheme Code to new Session Variable
Session.Add("SerialNumber", ds.Tables[0].Rows[0]["sno"].ToString());
//Set Update Flag
TaskFlag = "UPDATE";
//Fill values of selected record on the Entry Form
if (ds.Tables[0].Rows[0]["schm_code"].ToString().Length > 0)
lblSchemeCode.Text = ds.Tables[0].Rows[0]["schm_code"].ToString();
ddlType.SelectedValue = ds.Tables[0].Rows[0]["schemetype"].ToString(); ddlDistrict.Text = ds.Tables[0].Rows[0]["dist_nm"].ToString(); ddlBlock.Text = ds.Tables[0].Rows[0]["block_nm"].ToString();
txtSchemeName.Text = ds.Tables[0].Rows[0]["schm_nm"].ToString();
txtPopulation2001.Text = ds.Tables[0].Rows[0]["population_2001"].ToString();
txtSupplySource.Text = ds.Tables[0].Rows[0]["supply_source"].ToString();
txtApprovalYear.Text = ds.Tables[0].Rows[0]["yr_approval"].ToString();
txtApprovalLetterNum.Text = ds.Tables[0].Rows[0]["approval_letter_num"].ToString();
txtApprovalAmount.Text = ds.Tables[0].Rows[0]["sch_apr_amt"].ToString();
txtWaitedLetterNum.Text = ds.Tables[0].Rows[0]["sch_waited_details"].ToString();
txtSchTransferLetterNum.Text = ds.Tables[0].Rows[0]["schm_trans_details"].ToString();
txtSchTransferDate.Text = ds.Tables[0].Rows[0]["schm_trans_date"].ToString();
txtOtherRemarks.Text = ds.Tables[0].Rows[0]["remarks"].ToString();
}
catch (Exception ex)
{
ScriptManager.RegisterClientScriptBlock(this.Page, this.Page.GetType(), "Warning", "alert('" + ex.Message.ToString() + "');",true);
}
finally
{
ds.Dispose();
gridSerialNo = 0;
}
}
EDIT
There might be better approach to do so but this works certainly fine.

The way I would perform this task since you want to create a data access layer is to create a class which has all the properties
Class:
public class tw_main
{
public string SchemeCode {get;set;}
}
DAL:
public class dal
{
public tw_main getSelectedValue(pass the parameters required by the method)
{
//your connection and query code
var twmain = new tw_main();
twmain.SchemaCode = ds.Tables[0].Rows[0]["schm_code"].ToString();
return twmain;
}
}
Web Page:
//depending upon where you add this a reference may need to be imported (using) to the namespace
var dalObj = new dal();
var tw = dalObj.getSelectedValue();
lblSchemeCode.Text = tw.SchemaCode;