Need to create multiple dropdown list

krahman01 · June 21st, 2010, 10:13 PM

Seems like it's probably better not to use Masterpage when using JQuery!

Imar · June 22nd, 2010, 01:58 AM

No, i don't think that's the right conclusion. For stuff that needs to run on all or most pages, putting jQuery code in the Master Page makes a lot of sense. However, you need to be aware of the issue with the changed IDs. One way around this is to use class selectors in jQuery as opposed to ID selectors.

Cheers,

Imar

krahman01 · June 24th, 2010, 10:02 PM

Hi,

I created the third dropdown list, but it's blank now. Why is it not getting populated? I'm not using the Masterpage, just default.aspx and I updated pretty much everything else accordingly. New functions I added, for example...

--- function loadEmployeeCarColors(selectedItem) {
$.ajax({
type: "POST",
url: "Default.aspx/FetchEmployeeCarColors",
data: "{id: " + selectedItem + "}",
contentType: "application/json; charset=utf-8",
dataType: "json",
async: true,
success: function Success(data) {
printEmployeeCars(data.d);
}
});
}

function printEmployeeCarColors(data) {
$("select[name$=ddlEmployeeCarColors] > option").remove();
for (var i = 0; i < data.length; i++) {
$("select[name$=ddlEmployeeCarColors]").append(
$("<option></option>").val(data[i].Id).html(data[i].Car)
);
}
}
...

In the page_load, I have added...

---

var employees = new Employee();
var employeeCars = new EmployeeCar();
var employeeCarColors = new EmployeeCarColor();
ddlEmployee.DataSource = employees.FetchEmployees();
ddlEmployee.DataTextField = "Surname";
ddlEmployee.DataValueField = "Id";
ddlEmployee.DataBind();
---

I also added a class called EmployeeCarColor.cs with usual stuffs.

What could've gone wrong?

Imar · June 25th, 2010, 04:41 AM

Hi there,

Hard to tell without seeing how it all fits together. Have you tried debugging in Visual Studio? You should be able to "follow the wire" and find out if the right code is called and whether or not the right data gets passed back to the client.

Cheers,

Imar

krahman01 · June 29th, 2010, 09:28 PM

Ok, let's consider a scenario for third dropdown list driven from a database.

It's different data - here it's CarName, models and colors

For second dropdown I have a webservice [WebMethod] in CarsService.cs

Code:

    [WebMethod]
    public CascadingDropDownNameValue[] GetModelsByCarId(string knownCategoryValues,
        string category)
    {
        // Split the knownCategoryValues on ":" with ";" delimiter 
        // For the first dropdownlist, the values will be "undefined: id of the dropdownelement"
        // ex: "undefined: 13;"
        // The string at index 1 will be the CarId selected in the dropdownlist.
        string[] _categoryValues = knownCategoryValues.Split(':', ';');
        // Convert the element at index 1 in the string[] to get the CarId
        int _carID = Convert.ToInt32(_categoryValues[1]);
        // Create a List<T> of CascadingDropDownNameValue to hold the CarModels data
        List<CascadingDropDownNameValue> _carModels = new List<CascadingDropDownNameValue>();
        // Create an instance of CarModels TableAdapter
        dsCarModelsTableAdapters.CarModelsTableAdapter _carModelAdapter = new dsCarModelsTableAdapters.CarModelsTableAdapter();
        // For each datarow in the DataTable returned by the GetModelsByCarId method, add the modelname and modelid to the List<T>
        foreach (DataRow _row in _carModelAdapter.GetModelsByCarId(_carID))
        {
            _carModels.Add(new CascadingDropDownNameValue(_row["ModelName"].ToString(), _row["ModelId"].ToString()));
        }
        // convert to array and return the vlaues
        return _carModels.ToArray();
    }

now, if I create a [WebMethod] for third dropdown right underneath as:

//This is the third dropdown for
// getColorbymodelId
[WebMethod]
public CascadingDropDownNameValue[] GetColorsByModelId(string knownCategoryValues,
string category)
{
// Split the knownCategoryValues on ":" with ";" delimiter
// For the first dropdownlist, the values will be "undefined: id of the dropdownelement"
// ex: "undefined: 13;"
// The string at index 1 will be the CarId selected in the dropdownlist.
string[] _categoryValues = knownCategoryValues.Split(':', ';');
// Convert the element at index 1 in the string[] to get the CarId
int _modelID = Convert.ToInt32(_categoryValues[1]);
// Create a List<T> of CascadingDropDownNameValue to hold the CarColorss data
List<CascadingDropDownNameValue> _carColors = new List<CascadingDropDownNameValue>();
// Create an instance of CarColors TableAdapter
dsCarColorsTableAdapters.CarColorsTableAdapter _carColorAdapter = new dsCarColorsTableAdapters.CarColorsTableAdapter();
// For each datarow in the DataTable returned by the GetModelsByCarId method, add the modelname and modelid to the List<T>
foreach (DataRow _row in _carColorAdapter.GetColorsByModelId(_modelID))
{
_carColors.Add(new CascadingDropDownNameValue(_row["ColorName"].ToString(), _row["ColorId"].ToString()));
}
// convert to array and return the vlaues
return _carColors.ToArray();
}

I get the following two errors:

Error 86 The type or namespace name 'dsCarColorsTableAdapters' could not be found (are you missing a using directive or an assembly reference?) c:\inetpub\wwwroot\WebSiteDDL1\App_Code\CarsServic e.cs 72 9 http://localhost/WebSiteDDL1/

Error 87 The type or namespace name 'dsCarColorsTableAdapters' could not be found (are you missing a using directive or an assembly reference?) c:\inetpub\wwwroot\WebSiteDDL1\App_Code\CarsServic e.cs 72 79 http://localhost/WebSiteDDL1/

>> why does the same work for CarModels, but, not the car colors(3rd dropdown)

Imar · June 30th, 2010, 02:28 AM

The error about 'dsCarColorsTableAdapters' seems to suggest that you haven't added this adapter to your typed data set definitions? Where is dsCarModelsTableAdapters defined? That's where you also need to define dsCarColorsTableAdapters...

Imar

krahman01 · July 1st, 2010, 04:19 AM

That's exactly what I had the impression at first. But, the problem is that dsCarModelsTableAdapter is only defined in the

C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temp orary ASP.NET Files\websiteddl1\3091bb51\5ea88914\Sources_App_Co de\dscarmodels.xsd.72cecc2a.cs

That's kind of assembly file and I can't possibly add dsColor table Adapters there!

Here's the original article. He doesn't quite mention how to add TableAdapters in the article:

http://aspalliance.com/1183_Creating...Using_AJAX.all

Imar · July 1st, 2010, 04:28 AM

That assembly is generated based on the information for the typed datasets. You need to add another dataset yourself by following the steps in the section "Creating the datasets for accessing the Cars and CarModels data".

Hope this helps,

Imar

krahman01 · July 1st, 2010, 05:25 PM

The tableAdapter was already created, so was the dataset. Fail to understand why it doesn't see it!

krahman01 · July 1st, 2010, 05:32 PM

So after deleting the previously created and recreated the steps. Now, I get a different error message on the following code:

<code>
dsCarColorsTableAdapters.CarColorsTableAdapter _carColorAdapter = new dsCarColorsTableAdapters.CarColorsTableAdapter();
</code>

Error 55 The type or namespace name 'CarColorsTableAdapter' does not exist in the namespace 'dsCarColorsTableAdapters' (are you missing an assembly reference?) c:\inetpub\wwwroot\WebSiteDDL1\App_Code\CarsServic e.cs 72 34 http://localhost/WebSiteDDL1/
---
Error 56 The type or namespace name 'CarColorsTableAdapter' does not exist in the namespace 'dsCarColorsTableAdapters' (are you missing an assembly reference?) c:\inetpub\wwwroot\WebSiteDDL1\App_Code\CarsServic e.cs 72 104 http://localhost/WebSiteDDL1/