Concatinate two Values in a dropdown list with a datasource of ListCollection

Question

User709166883 posted

Anyone please tell me in detail how to setup a multi value dropdownlist from  a list collection...

Datasource: Listcollection which contains ColorCode and Description...

how setup a dropdown with Colorcode-Description like BLK-Black...

then how to capture these selected value as colorcode only by removing description for update purpose...

Now I am doin like this...

ddl.datesource=list<datasetvalues> ...contains (colorcode, description)

ddl.DataTextField = "ColorCode";

ddl.DataValueField = "ColorCode";

ddl.databind();

then selected value should be like this...

ddlcolor.Items.FindByValue((DataBinder.Eval(formView1.DataItem, "colorCode").ToString())).Selected = true;

for update:

ClassA.Color= ddl.selectedvalue();

Now what I need change to in the above code to get the combination of both..otherwise i need have textbox for description which syncs with ddl..which is bit complex for my level of programming...thanks..

Answer 1

User1224194097 posted

ddl.datesource=list<datasetvalues> ...contains (colorcode, description)

 

What is that ListCollection based on? DataSet or a List with two properties ColorCode and Description. You can handle this in many ways. One simple way is creating a temp list with new property like this. I am assuming that listCollection is obtained from a DataTable.

Add these import statements

using System.Data;
using System.Linq;

DataTable DataTable1 = new DataTable();
DropDownList1.DataSource = DataTable1.AsEnumerable().Select(a => new
{
    ColorCode = Convert.ToString(a["ColorCode"]),
    ColorDescription = Convert.ToString(a["ColorDescription"]),
    DisplayText = String.Format("{0}-{1}", Convert.ToString(a["ColorCode"]), Convert.ToString(a["ColorDescription"]))
}).ToList();
DropDownList1.DataTextField = "DisplayText";
DropDownList1.DataValueField = "ColorCode";
DropDownList1.DataBind();

You can find the ListItem by Value which is ColorCode and update DB. New Column DisplayText is solely for just showing the description. That's it.

Answer 2

User709166883 posted

hello Santhosh,

Thanks for your reply...

Its a data set...came from Dataacess layer and I am converting it to list<colorclass> in business....

your solution makes some hope for me...and will u please provie me other way..because I am converting datset to list then again i need to store it to datatable....I don't know is it a good practice...can I do the same operation on the list???

and please show some piece of code how to capture that value on code behind...do i need to any trimming kind of things..I don't know...Thnks again...

Answer 3

User1224194097 posted

will u please provie me other way..

 

It is difficult to visualize how you are retrieving the values from DataTable/DataSet.

I am converting datset to list then again i need to store it to datatable....

You do not need to convert dataset to list and list to datatable etc., using LINQ, you can just build a List with an ADDITIONAL PROPERTY for DISPLAYTEXT. Add a new Property DISPLAYTEXT or some other name. You can just use a DataReader and return a List of ColorClass Objects. That's it. Avoiding DataTables is a different approach altogether. You can use your existing code to add display Text like this

DropDownList1.DataSource = DataTable1.AsEnumerable().Select(a => new ColorClass()
{
    ColorCode = Convert.ToString(a["ColorCode"]),
    ColorDescription = Convert.ToString(a["ColorDescription"]),
    DisplayText = String.Format("{0}-{1}", Convert.ToString(a["ColorCode"]), Convert.ToString(a["ColorDescription"]))
}).ToList();
DropDownList1.DataTextField = "DisplayText";
DropDownList1.DataValueField = "ColorCode";
DropDownList1.DataBind();

please show some piece of code how to capture that value on code behind...do i need to any trimming kind of things..

 DropDownList1.SelectedValue gives color Code. You do not need any trimming or string manipulation.

Answer 4

User709166883 posted

This is my code..please check this...u can get an idea...Thank You Very Much..

BLL Method:

public List<IColor> GetColorCode()
        {
            dataset = DAL.GetColorCode();
            List<IColor> collection = new List<IColor>();

            if (dataset != null)
            {
                if (dataset.Tables[0].Rows.Count > 0)
                {
                    for (int i = 0; i < dataset.Tables[0].Rows.Count; i++)
                    {
                        collection.Add(new Color
                        {
                            ColorCode = dataset.Tables[0].Rows[i]["ColorCode"].ToString(),
                            Description = dataset.Tables[0].Rows[i]["Description"].ToString()

                        });
                    }
                }
            }
            return collection;
        }

DAL returns dataset which is ADO.Net method with connection strings and calling stored procs...etc...I think U can Imagine how this looks like...

In page codebehind:

DropDownList ddlColorCode= ((DropDownList)formViewJewelryEditItems.FindControl("ddlColorCode"));
ddlColorCode.DataSource = BAL.GetColorCode();
ddlColorCode.DataTextField = "ColorCode";
ddlColorCode.DataValueField = "ColorCode";
ddlColorCode.DataBind();

Answer 5

User1224194097 posted

Add a new property for Color Class with property name Display Text

private string m_ColorDisplayText = "";
public string ColorDisplayText
{
    get
    {
        return m_ColorDisplayText;
    }
    set
    {
        m_ColorDisplayText = value;
    }
}

and modify the BL method like this

public List<IColor> GetColorCode()
{
    dataset = DAL.GetColorCode();
    List<IColor> collection = new List<IColor>();
    if (dataset != null)
    {
        if (dataset.Tables[0].Rows.Count > 0)
        {
            for (int i = 0; i < dataset.Tables[0].Rows.Count; i++)
            {
                collection.Add(new Color
                {
                    ColorCode = dataset.Tables[0].Rows[i]["ColorCode"].ToString(),
                    Description = dataset.Tables[0].Rows[i]["Description"].ToString(),
                    ColorDisplayText = String.Format("{0}-{1}", dataset.Tables[0].Rows[i]["ColorCode"].ToString(),
                                                                dataset.Tables[0].Rows[i]["Description"].ToString())
                });
            }
        }
    }
    return collection;
}

 And Set DropDownList DataTextField to ColorDisplayText and DataValueField to ColorCode.

DropDownList1.DataTextField = "DisplayText";
DropDownList1.DataValueField = "ColorCode";
DropDownList1.DataBind();

That's it.

Answer 6

User709166883 posted

ohhh..got it...great santhosh...excellent...this thing killing me from yesterday....thanks for n times...

-Sunny

Answer 7

User-233499379 posted

how is this done in MVC?