I'm curious as to the best route (more looking towards simplicity, not speed or efficiency) to sort a DropDownList in C#/ASP.NET - I've looked at a few recommendations but they aren't clicking well with me.
Edit: Folks, I do not have control over how the data comes into the DropDownList - I cannot modify the SQL.
If you get a DataTable with the data, you can create a DataView off of this and then bind the drop down list to that. Your code would look something like...
DataView dvOptions = new DataView(DataTableWithOptions);
dvOptions.Sort = "Description";
ddlOptions.DataSource = dvOptions;
ddlOptions.DataTextField = "Description";
ddlOptions.DataValueField = "Id";
ddlOptions.DataBind();
Your text field and value field options are mapped to the appropriate columnns in the data table you are receiving.
A C# solution for .NET 3.5 (needs System.Linq and System.Web.UI):
public static void ReorderAlphabetized(this DropDownList ddl)
{
List<ListItem> listCopy = new List<ListItem>();
foreach (ListItem item in ddl.Items)
listCopy.Add(item);
ddl.Items.Clear();
foreach (ListItem item in listCopy.OrderBy(item => item.Text))
ddl.Items.Add(item);
}
Call it after you've bound your dropdownlist, e.g. OnPreRender:
protected override void OnPreRender(EventArgs e)
{
base.OnPreRender(e);
ddlMyDropDown.ReorderAlphabetized();
}
Stick it in your utility library for easy re-use.
Assuming you are running the latest version of the .Net Framework this will work:
List<string> items = GetItemsFromSomewhere();
items.Sort((x, y) => string.Compare(x, y));
DropDownListId.DataSource = items;
DropDownListId.DataBind();
DropDownList takes any IEnumerable as a DataSource.
Just sort it using LINQ.
I usually load a DropDownList with values from a database table, so the easiest way is to sort your results as desired with the ORDER BY clause of your SELECT statement, and then just iterate through the results and dump them into the DropDownList.
Take a look at the this article from CodeProject, which rearranges the content of a dropdownlist. If you are databinding, you will need to run the sorter after the data is bound to the list.
It is recommended to sort the data before databinding it to the DropDownList but in case you can not, this is how you would sort the items in the DropDownList.
First you need a comparison class
Public Class ListItemComparer
Implements IComparer(Of ListItem)
Public Function Compare(ByVal x As ListItem, ByVal y As ListItem) As Integer _
Implements IComparer(Of ListItem).Compare
Dim c As New CaseInsensitiveComparer
Return c.Compare(x.Text, y.Text)
End Function
End Class
Then you need a method that will use this Comparer to sort the DropDownList
Public Shared Sub SortDropDown(ByVal cbo As DropDownList)
Dim lstListItems As New List(Of ListItem)
For Each li As ListItem In cbo.Items
lstListItems.Add(li)
Next
lstListItems.Sort(New ListItemComparer)
cbo.Items.Clear()
cbo.Items.AddRange(lstListItems.ToArray)
End Sub
Finally, call this function with your DropDownList (after it's been databound)
SortDropDown(cboMyDropDown)
P.S. Sorry but my choice of language is VB. You can use http://converter.telerik.com/ to convert the code from VB to C#
Another option is to put the ListItems into an array and sort.
int i = 0;
string[] array = new string[items.Count];
foreach (ListItem li in dropdownlist.items)
{
array[i] = li.ToString();
i++;
}
Array.Sort(array);
dropdownlist.DataSource = array;
dropdownlist.DataBind();
I agree with sorting using ORDER BY when populating with a database query, if all you want is to sort the displayed results alphabetically. Let the database engine do the work of sorting.
However, sometimes you want some other sort order besides alphabetical. For example, you might want a logical sequence like: New, Open, In Progress, Completed, Approved, Closed. In that case, you could add a column to the database table to explicitly set the sort order. Name it something like SortOrder or DisplaySortOrder. Then, in your SQL, you'd ORDER BY the sort order field (without retrieving that field).
What kind of object are you using for databinding? Typically I use Collection<T>, List<T>, or Queue<T> (depending on circumstances). These are relatively easy to sort using a custom delegate. See MSDN documentation on the Comparison(T) delegate.
var list = ddl.Items.Cast<ListItem>().OrderBy(x => x.Text).ToList();
ddl.DataSource = list;
ddl.DataTextField = "Text";
ddl.DataValueField = "Value";
ddl.DataBind();
Try it
-------Store Procedure-----(SQL)
USE [Your Database]
GO
CRATE PROC [dbo].[GetAllDataByID]
#ID int
AS
BEGIN
SELECT * FROM Your_Table
WHERE ID=#ID
ORDER BY Your_ColumnName
END
----------Default.aspx---------
<asp:DropDownList ID="ddlYourTable" runat="server"></asp:DropDownList>
---------Default.aspx.cs-------
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
List<YourTable> table= new List<YourTable>();
YourtableRepository tableRepo = new YourtableRepository();
int conuntryInfoID=1;
table= tableRepo.GetAllDataByID(ID);
ddlYourTable.DataSource = stateInfo;
ddlYourTable.DataTextField = "Your_ColumnName";
ddlYourTable.DataValueField = "ID";
ddlYourTable.DataBind();
}
}
-------LINQ Helper Class----
public class TableRepository
{
string connstr;
public TableRepository()
{
connstr = Settings.Default.YourTableConnectionString.ToString();
}
public List<YourTable> GetAllDataByID(int ID)
{
List<YourTable> table= new List<YourTable>();
using (YourTableDBDataContext dc = new YourTableDBDataContext ())
{
table= dc.GetAllDataByID(ID).ToList();
}
return table;
}
}
I agree with the folks in sorting your data in the model before populating them to the DropDownList, so if you are populating this from a DB, it is a good thing to get them sorted already there using a simple order by clause, it will save you some cycles in the web server, and I am sure the DB will do it so much faster.
If you are populating this from another data source for example, XML file, using LINQ will be a good idea, or even any variation of Array.Sort will be good.
If your data is coming to you as a System.Data.DataTable, call the DataTable's .Select() method, passing in "" for the filterExpression and "COLUMN1 ASC" (or whatever column you want to sort by) for the sort. This will return an array of DataRow objects, sorted as specified, that you can then iterate through and dump into the DropDownList.
List<ListItem> li = new List<ListItem>();
foreach (ListItem list in DropDownList1.Items)
{
li.Add(list);
}
li.Sort((x, y) => string.Compare(x.Text, y.Text));
DropDownList1.Items.Clear();
DropDownList1.DataSource = li;
DropDownList1.DataTextField = "Text";
DropDownList1.DataValueField = "Value";
DropDownList1.DataBind();
To sort an object datasource that returns a dataset you use the Sort property of the control.
Example usage In the aspx page to sort by ascending order of ColumnName
<asp:ObjectDataSource ID="dsData" runat="server" TableName="Data"
Sort="ColumnName ASC" />
is better if you sort the Source before Binding it to DropDwonList.
but sort DropDownList.Items like this:
Dim Lista_Items = New List(Of ListItem)
For Each item As ListItem In ddl.Items
Lista_Items.Add(item)
Next
Lista_Items.Sort(Function(x, y) String.Compare(x.Text, y.Text))
ddl.Items.Clear()
ddl.Items.AddRange(Lista_Items.ToArray())
(this case i sort by a string(the item's text), it could be the suplier's name, supplier's id)
the Sort() method is for every List(of ) / List<MyType>, you can use it.
You can do it this way is simple
private void SortDDL(ref DropDownList objDDL)
{
ArrayList textList = new ArrayList();
ArrayList valueList = new ArrayList();
foreach (ListItem li in objDDL.Items)
{
textList.Add(li.Text);
}
textList.Sort();
foreach (object item in textList)
{
string value = objDDL.Items.FindByText(item.ToString()).Value;
valueList.Add(value);
}
objDDL.Items.Clear();
for(int i = 0; i < textList.Count; i++)
{
ListItem objItem = new ListItem(textList[i].ToString(), valueList[i].ToString());
objDDL.Items.Add(objItem);
}
}
And call the method this SortDDL(ref yourDropDownList);
and that's it. The data in your dropdownlist will be sorted.
see http://www.codeproject.com/Articles/20131/Sorting-Dropdown-list-in-ASP-NET-using-C#
You can use this JavaScript function:
function sortlist(mylist)
{
var lb = document.getElementById(mylist);
arrTexts = new Array();
arrValues = new Array();
arrOldTexts = new Array();
for(i=0; i<lb.length; i++)
{
arrTexts[i] = lb.options[i].text;
arrValues[i] = lb.options[i].value;
arrOldTexts[i] = lb.options[i].text;
}
arrTexts.sort();
for(i=0; i<lb.length; i++)
{
lb.options[i].text = arrTexts[i];
for(j=0; j<lb.length; j++)
{
if (arrTexts[i] == arrOldTexts[j])
{
lb.options[i].value = arrValues[j];
j = lb.length;
}
}
}
}
Try This:
/// <summary>
/// AlphabetizeDropDownList alphabetizes a given dropdown list by it's displayed text.
/// </summary>
/// <param name="dropDownList">The drop down list you wish to modify.</param>
/// <remarks></remarks>
private void AlphabetizeDropDownList(ref DropDownList dropDownList)
{
//Create a datatable to sort the drop down list items
DataTable machineDescriptionsTable = new DataTable();
machineDescriptionsTable.Columns.Add("DescriptionCode", typeof(string));
machineDescriptionsTable.Columns.Add("UnitIDString", typeof(string));
machineDescriptionsTable.AcceptChanges();
//Put each of the list items into the datatable
foreach (ListItem currentDropDownListItem in dropDownList.Items) {
string currentDropDownUnitIDString = currentDropDownListItem.Value;
string currentDropDownDescriptionCode = currentDropDownListItem.Text;
DataRow currentDropDownDataRow = machineDescriptionsTable.NewRow();
currentDropDownDataRow["DescriptionCode"] = currentDropDownDescriptionCode.Trim();
currentDropDownDataRow["UnitIDString"] = currentDropDownUnitIDString.Trim();
machineDescriptionsTable.Rows.Add(currentDropDownDataRow);
machineDescriptionsTable.AcceptChanges();
}
//Sort the data table by description
DataView sortedView = new DataView(machineDescriptionsTable);
sortedView.Sort = "DescriptionCode";
machineDescriptionsTable = sortedView.ToTable();
//Clear the items in the original dropdown list
dropDownList.Items.Clear();
//Create a dummy list item at the top
ListItem dummyListItem = new ListItem(" ", "-1");
dropDownList.Items.Add(dummyListItem);
//Begin transferring over the items alphabetically from the copy to the intended drop
downlist
foreach (DataRow currentDataRow in machineDescriptionsTable.Rows) {
string currentDropDownValue = currentDataRow["UnitIDString"].ToString().Trim();
string currentDropDownText = currentDataRow["DescriptionCode"].ToString().Trim();
ListItem currentDropDownListItem = new ListItem(currentDropDownText, currentDropDownValue);
//Don't deal with dummy values in the list we are transferring over
if (!string.IsNullOrEmpty(currentDropDownText.Trim())) {
dropDownList.Items.Add(currentDropDownListItem);
}
}
}
This will take a given drop down list with a Text and a Value property of the list item and put them back into the given drop down list.
Best of Luck!
If you are adding options to the dropdown one by one without a dataset and you want to sort it later after adding items, here's a solution:
DataTable dtOptions = new DataTable();
DataColumn[] dcColumns = { new DataColumn("Text", Type.GetType("System.String")),
new DataColumn("Value", Type.GetType("System.String"))};
dtOptions.Columns.AddRange(dcColumns);
foreach (ListItem li in ddlOperation.Items)
{
DataRow dr = dtOptions.NewRow();
dr["Text"] = li.Text;
dr["Value"] = li.Value;
dtOptions.Rows.Add(dr);
}
DataView dv = dtOptions.DefaultView;
dv.Sort = "Text";
ddlOperation.Items.Clear();
ddlOperation.DataSource = dv;
ddlOperation.DataTextField = "Text";
ddlOperation.DataValueField = "Value";
ddlOperation.DataBind();
This would sort the dropdown items in alphabetical order.
If you are using a data bounded DropDownList, just go to the wizard and edit the bounding query by:
Goto the .aspx page (design view).
Click the magic Arrow ">"on the Dropdown List.
Select "Configure Data source".
Click Next.
On the right side of the opened window click "ORDER BY...".
You will have up two there field cariteria to sort by. Select the desired field and click OK, then click Finish.
You may not have access to the SQL, but if you have the DataSet or DataTable, you can certainly call the Sort() method.
Related
I have a dropdownlist where I want to display a list of users. To call the users I use ChatUserDetails.GetPXPUsers()
Which brings me to this code:
public static List<ChatUserDetails> GetPXPUsers()
{
List<ChatUserDetails> Users = new List<ChatUserDetails>();
string SQL = SelectPXPUsers;
DataTable dtMainItems = ChatUserDetails.CustomFill(SQL, null);
foreach (DataRow dr in dtMainItems.Rows)
{
Users.Add(new ChatUserDetails(dr));
}
return Users;
}
But how to I display this list of users in my dropdownlist?
<asp:DropDownList runat="server" ID="DropDownListPXPUsers"></asp:DropDownList>
You can bind your list to your drop down at runtime by using the following code. You will need to specify which properties of the object are to be used.
DropDownListPXPUsers.DataSource = GetPXPUsers();
DropDownListPXPUsers.DateTextField = "PropertyOne"; // name of 'ChatUserDetails' property
DropDownListPXPUsers.DataValueField = "PropertyTwo"; // name of 'ChatUserDetails' property
DropDownListPXPUsers.DataBind();
Read more: See Examples in the DropDownList documentation.
First you'll need to set the DataSource for the DropDownList and then you will need to call DataBind().
if(!IsPostBack)
{
DropDownListPXPUsers.DataSource = GetPXPUsers();
DropDownListPXPUsers.DataBind();
}
I have a combobox and a datatable.
I've added all of the elements of one column in the datatable to the combobox items.
Now whenever the user chooses a item in the combobox, I want to go to the datatable and compare the column, if there's a match, it will do some code.
I have the following
private void comboBox8_SelectedIndexChanged(object sender, EventArgs e)
{
string str = comboBox8.SelectedItem.ToString();
int z = 0;
foreach (var row in datatable.Rows)
{
int i = 0; i++;
if (datatable.Rows[row]["Cidade"] == str)
{
z = i;
}
}
}
"Cidade" is the column name that matches the options in the combobox.
The Problem is that the code doesn't identify the ìf` condition as valid, saying there are invalid arguments
Edit: worked it around like this:
private void comboBox8_SelectedIndexChanged(object sender, EventArgs e)
{
string str = comboBox8.SelectedItem.ToString();
int z = 0;
for (int i = 0; i < DataAccess.Instance.tabelasismica.Rows.Count; i++)
{
if (DataAccess.Instance.tabelasismica.Rows[i]["Cidade"] == str)
{
z = i;
}
}
MessageBox.Show(z.ToString());
MessageBox.Show(DataAccess.Instance.tabelasismica.Rows[z]["Cidade"].ToString());
}
Standard way of doing things like this is to use data-binding. You'd simply set your ComboBox's DataSource to your DataTable. The code would roughly look like this:
comboBox8.DataSource = datatable;
comboBox8.DisplayMember = "Cidade"
comboBox8.ValueMember = "PrimaryKeyColumnOfYourTable"
Now in the SelectedIndexChanged event, you simply use comboBox8.SelectedValue property to get the ID of the selected row. If you have strongly typed DataSet, your DataTable will have a function named FindByYourPKColumn() that you can use to find the row using this ID.
datatable.Rows[row]["Cidade"] is of type object - you need to convert it to a string before comparing it to str, like this:
if (datatable.Rows[row]["Cidade"].ToString() == str)
{ ... }
Try this in place of the for loop
foreach (DataRow row in dDataAccess.Instance.tabelasismica.Rows)
{
if (row["Cidade"].ToString() == str)
{
z = dDataAccess.Instance.tabelasismica.Rows.IndexOf(row);
}
}
or
foreach (DataRow row in dataTable.Rows)
{
if (row["Cidade"].ToString() == str)
{
z = dataTable.Rows.IndexOf(row);;
}
}
Being said that, standard practice in using ComboBoxes, ListBoxes etc with datasources is to to have a distinct column in the data-table assigned as the ValueMember of the ComboBox, which makes life even easier - as suggested by #dotNET.
comboBox8.DataSource= dataTable; //the data table which contains data
comboBox8.ValueMember = "id"; // column name which you want in SelectedValue
comboBox8.DisplayMember = "name"; // column name that you need to display as text
That way you don't have to iterate through the dataTable to find the index of the row, and you can use the ID (ValueMember) to continue process as required.
Example here
#dotNET's answer is the preferred method to solve your specific problem.
However to solve the general problem find a value in a dataset your best bets are to either
Use the ADO.NET methods Find or Select e.g.
var results = dataset.Select(string.Format("Cidade = {0}",str));
if (results.Count() != 0 )
{
...
}
Or use System.Data.DataSetExtensions
if (datatable.AsEnumerable().Any( x=> x.Field<string>("Cidade") == str ))
{
....
}
In my DataGrid I used a ComboBox in the first column, so it will fetch some data from the database using the DisplayMember and ValueMember concepts. Now I want to remove the value from the ComboBox which is previously selected.
Populating the ComboBox code is given below:
dTable = getDummyTable.GetDummyTble("Dummy", "DNO", "All");
dCmbData = dTable;
cmbDeno.DataSource = dTable;
cmbDeno.DisplayMember = "dyName";
cmbDeno.ValueMember = "dyRemarks";
The next row of selection there should not be a duplicate value in the ComboBox.
How can I achieve this?
Can anyone help me with this?
well try this one out. You have the DataTable which you are using to bind all combos (correct me if I'm wrong). Now all we need to do is that when an item is selected from any combo, we need to remove that item from all the other combos). You will need to declare a class level dictionary to store which combo had what value stored previously:
IDictionary<ComboBox, DataRow> _prevSelection;
//Please don't mind if syntax is wrong worked too long in web
comboBox.OnSelectedIndexChanged += fixItems;
private void fixItems(object sender, EventArgs e)
{
var cbo= sender as ComboBox;
if(cbo==null) return;
var prev = _prevSelection[cbo];
var row=<GET ROW FROM DATATABLE FOR CURRENT SELECTED VALUE>;
_prevSelection[cbo] = row;
UpdateOtherCombos(cbo, prev, cbo.SelectedItem.Value);
}
private void UpdateOtherCombos(ComboBox cbo, DataRow prev, object toRemove)
{
foreach(var gridrow in <YourGrid>.Rows)
{
var c = <FIND COMBO IN ROW>;
if(cbo.Id == c.Id) continue;//combo that triggered this all
var itemToRemove=null;
foreach(var item in c.Items)
{
if(item.Value == toRemove)
{
itemToRemove = item;
break;
}
}
//or you can get index of item and remove using index
c.Items.Remove(itemToRemove);
//Now add the item that was previously selected in this combo (that
//triggered this all)
c.Items.Add(new ComboBoxItem{Value = prev["ValueColumn"],
Text = prev ["TextColumn"]});
}
}
This is just to give you an idea that may help you to find an optimal solution rather than iterating over all combos as it will slow down if you have too many rows in grid or too many items in combos. Still even with this you need to put up some functions/code to make it working. Also please note that I have not worked on WinForms for some time and you need to check if things like ComboBoxItem etc. and any functions called on them exist. :)
I have a ComboBox with the following code:
private void comboBox1_TextChanged(object sender, EventArgs e)
{
using (var service = WebServiceHelper.GetCoreService())
{
string physicianXml = service.SearchPhysicians(SessionInfo.Current.ClientCode, SessionInfo.Current.MachineName,
SessionInfo.Current.Username, comboBox1.Text);
var physicians = PhysicianItemList.FromXml(physicianXml);
AutoCompleteStringCollection autoCompleteStringCollection = new AutoCompleteStringCollection();
foreach (var physician in physicians.Items)
{
autoCompleteStringCollection.Add(physician.LastName + ", " + physician.FirstName);
}
comboBox1.AutoCompleteCustomSource = autoCompleteStringCollection;
comboBox1.Select(comboBox1.Text.Length, 0);
}
}
Basically, a user types the first few characters of a physician's name and it should populate the auto-complete list with the top 100 matching records. It works great, but I need to associate it back to a key (either the PK from the table, or the Physician's NPI number). It seems the AutoCompleteStringCollection doesn't support keys. Can anyone suggest a way of doing this? There are approximately 7 million records in the table, so I don't want to prepopulate the ComboBox.
Thanks
When you build your AutoCompleteStringCollection, build a Dictionary<String, int> for the name, id pairs as well. Then use some event (textbox validation or user submit/save click) to lookup and set the id. You could store the dictionary on the textbox Tag.
Edit
For some reason I thought you were working with a textbox control. Forget about the AutoCompleteStringCollection and just build a Dictionary<String, int>. For the combobox set your autocompletesource to ListItems, set the combobox display name and value and set the datasource to the dictionary.
combobox.DisplayMember = "key";
combobox.ValueMember = "value";
combobox.AutocompleteSource = AutocompleteSource.ListItems;
combobox.DataSource = myDictionary;
However you should only populate the datasource and autocomplete once when the user enters n characters in the combobox, otherwise it gets buggy. I tried to use this for a dynamic autocomplete once (eg the list clears if the user clear the text and retypes), but I had to forget about the combobox and use a hybrid textbox listbox approach much like this user
It looks like your problem is that AutoCompleteStringComplete was made specifically for strings (hence, the name).
You may want to look into the parents (IList, ICollection, IEnumerable) and see if you can homebrew something templated toward a key/value struct.
Too late but maybe someone will use this code :
this.AutoCompleteSource = System.Windows.Forms.AutoCompleteSource.ListItems;
this.AutoCompleteMode = System.Windows.Forms.AutoCompleteMode.SuggestAppend;
RNProveedor rnProveedor = new RNProveedor();
var listaProveedores = rnProveedor.Buscar();
Dictionary<int, String> dicTemp = new Dictionary<int, string>();
foreach (var entidad in listaProveedores)
{
dicTemp.Add(entidad.ProvNro, entidad.ProNombre);
}
this.DataSource = new BindingSource(dicTemp, null);
this.DisplayMember = "Value";
this.ValueMember = "Key";
And to select the value
public int GetValorDecimal()
{
KeyValuePair<int, string> objeto = (KeyValuePair<int, string>)this.SelectedItem;
return objeto.Key;
}
With this example you won't have any problem with duplicated strings as the examples above
hey guys,Actually i have two comboboxes having same elements but i have used two datasets having same elements.Now when i bind combobox with dataset ,it repeats its elements.
Can anyone help me to sort it out?
my code goes like this:
DataSet ds_PromotionDesignation = new DataSet();
ds_PromotionDesignation = EPI.comboDeg();
cmbPromotionDesignationFrom.DataSource = ds_PromotionDesignation.Tables[0];
cmbPromotionDesignationFrom.DisplayMember = "DEG_NAME";
cmbPromotionDesignationFrom.ValueMember = "DEG_ID";
cmbPromotionDesignationFrom.SelectedIndex = -1;
DataSet ds_PromotionDesignationTo = new DataSet();
ds_PromotionDesignationTo = EPI.PromotionDesignationTo();
foreach (DataRow row in ds_PromotionDesignationTo.Tables["tbl_org_Desg"].Rows)
{
myAL.Add(new USState(row["DEG_ID"].ToString(),row["DEG_NAME"].ToString()));
}
cmbPromotionDesignationTo.DataSource = myAL;
cmbPromotionDesignationTo.DisplayMember = "DEGNAME";
cmbPromotionDesignationTo.ValueMember = "DEGID";
Looking at your code it looks like you want to transfer ownership of an item from one guy to another, using two combos that both populate the same list of data.
You want to exclude the selected item form the destination combo. Try in the foreach loop, to only add an item if it is not the same as the current selected value, something like this (untested)
foreach (DataRow row in ds_PromotionDesignationTo.Tables["tbl_org_Desg"].Rows)
{
if ((int)row["DEG_ID"] != (int)cmbPromotionDesignationFrom.SelectedValue)
{
myAL.Add(new USState(row["DEG_ID"].ToString(), row["DEG_NAME"].ToString()));
}
}