How set value of DropDown after getting the list

Bryan Gomez

8y3.1k.NET

I need to set value of the dropdown after getting the list for dataset. But I'm having an error of:

The ViewData item that has the key 'txtCustomer' is of type 'System.String' but must be of type 'IEnumerable'

Here's my Controller:

wmsSR = new WMSSOFT_WCF_Service.WMSSOFT_InterfaceClient();
dsl = new DataSet();
dsO = new DataSet();
a = "GetSRMCustomers";
b = string.Empty;
//b = wmsSR.fCallWMSSOFTService(a, null, ref dsl, ref dsO);
b = wmsSR.fCallWMSSOFTService(a, "", ref dsl, ref dsO);
if (b == "OK ~~")
{
if (dsO.Tables[0].Rows.Count >= 0)
{
List item = new List();
for (int i = 0; i < dsO.Tables[0].Rows.Count; i++)
{
item.Add(new SelectListItem { Text = dsO.Tables[0].Rows[i]["NAMECUST"].ToString(), Value = dsO.Tables[0].Rows[i]["IDCUST"].ToString().Replace(" ", String.Empty) });
}
ViewBag.txtCustomer = item;
ViewBag.txtCustomer = "ABC ";
}
}

5 Replies

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Asma Khalid8y ago
You are getting a valid error because you are setting a string value to the IEnumerable type structure and I am also assuming that you are not properly mapping model to the dropdown list control, you are trying to map default value via ViewBag instead of via model.

So, correct aproach to achieve this behavior is that, In your action method you need to set your default value of dropdown as follow i.e.
public ActionResult Index()
        {
            // Initialization.
            DropdownViewModel model = new DropdownViewModel();

            // Settings.
            model.SelectedCode = "OEC";

            // Loading drop down lists.
            this.ViewBag.MyList = this.GetMyList();

            // Info.
            return this.View(model);
        }
Then you need to set your HTML code for dropdown like following i.e.
@Html.DropDownListFor(m => m.SelectedCode, this.ViewBag.MyList as SelectList, new { @class = "form-control" })
notice in the above code as I have attached dropdown list as a model to my HTML Razor control. So, I have setted my default value as SelectedCode which will be mapped as default value on the dropdown list and which is also the VALUE attribute. If i have not provided any value then nothing would have been selected on my dropdownload list. And also note here that the value attribute here I have used as string so, when Razor control maps my set value to my dropdown list it knows that the value attribute in my dropdown list is string.
For detail flow of using dropdownlist. You can explore following link http://bit.ly/2fzMWjE
0
Nilesh Patil8y ago
Hi,
refer both links

https://stackoverflow.com/questions/6625356/adding-a-default-value-in-dropdownlist-after-binding-with-database

https://stackoverflow.com/questions/14105265/dropdownlist-datasource
0
Asma Khalid8y ago
This might help http://bit.ly/2fzMWjE
0
Bryan Gomez8y ago
What I mean here is that, I need to set the default value of the dropdown.

For example here are my list from the dataset:
Code Value
ABC
Company ABC
OEC
OEC Company
Acme
Team Acme

I want to default the OEC in my dropdown. I'm having that error if I put this line at the buttom
ViewBag.txtCustomer = "ABC ";
But, when I removed that. The loading of the page is as expected.
0
Nilesh Patil8y ago
Hi,

Refer this link

https://stackoverflow.com/questions/14700861/the-viewdata-item-that-has-the-key-maritalstatus-is-of-type-system-string-bu
0

Code	Value
ABC	Company ABC
OEC	OEC Company
Acme	Team Acme