Re: how i get data from datatable - C# Discussion Boards

13-Jan-13 6:58

let's say i have two columns,one called area and second called city .i want to get all the cities when i choos a Specific area .
i use with datatable and i don't know how to Formulate an sql Query.it's suppose to be like that:

string areaName = DropDownList1.Items[DropDownList1.SelectedIndex].ToString().Trim();
        DataRow[] city = dt.Select("city_name where area='"+areaName+"'");
        for (int i = 0; i < city.Count<DataRow>(); i++)
        {
            DropDownList2.Items.Add(city[i]["city_name"].ToString());
        }

PIEBALDconsult13-Jan-13 13:38

PIEBALDconsult

13-Jan-13 13:38

I can't quite tell what you are trying to do there, but (dt is a DataTable, right?) you could try:

dt.DefaultView.RowFilter = "area=" + areaname ;
DropDownList2.DataSource = dt.DefaultView ;

Edit: Here's a full working example.

            System.Data.DataRow dr ;

// Define a State table
            System.Data.DataTable state = new System.Data.DataTable("State");
            state.Columns.Add(new System.Data.DataColumn("ID",typeof(int)));
            state.Columns.Add(new System.Data.DataColumn("Name",typeof(string)));

// Add some rows
            dr = state.NewRow() ;
            dr [ "ID" ] = 1 ;
            dr [ "Name" ] = "Arizona" ;
            state.Rows.Add ( dr ) ;

            dr = state.NewRow() ;
            dr [ "ID" ] = 2 ;
            dr [ "Name" ] = "California" ;
            state.Rows.Add ( dr ) ;

// Set the first ComboBox to display the table
            this.comboBox1.DataSource = state.DefaultView ;
            this.comboBox1.DisplayMember = "Name" ;

// Define a City table
            System.Data.DataTable city = new System.Data.DataTable("State");
            city.Columns.Add(new System.Data.DataColumn("ID",typeof(int)));
            city.Columns.Add(new System.Data.DataColumn("State",typeof(int)));
            city.Columns.Add(new System.Data.DataColumn("Name",typeof(string)));

// Add some rows
            dr = city.NewRow() ;
            dr [ "ID" ] = 1 ;
            dr [ "State" ] = 1 ;
            dr [ "Name" ] = "Phoenix" ;
            city.Rows.Add ( dr ) ;

            dr = city.NewRow() ;
            dr [ "ID" ] = 2 ;
            dr [ "State" ] = 1 ;
            dr [ "Name" ] = "Tucson" ;
            city.Rows.Add ( dr ) ;

            dr = city.NewRow() ;
            dr [ "ID" ] = 3 ;
            dr [ "State" ] = 2 ;
            dr [ "Name" ] = "San Diego" ;
            city.Rows.Add ( dr ) ;

            dr = city.NewRow() ;
            dr [ "ID" ] = 4 ;
            dr [ "State" ] = 2 ;
            dr [ "Name" ] = "Los Angeles" ;
            city.Rows.Add ( dr ) ;

// Set the second ComboBox to display the table
            this.comboBox2.DataSource = city.DefaultView ;
            this.comboBox2.DisplayMember = "Name" ;

// Add a SelectedIndexChanged handler
            this.comboBox1.SelectedIndexChanged += delegate ( object sender , System.EventArgs e )
            {
                System.Data.DataRowView item = this.comboBox1.SelectedItem as System.Data.DataRowView ;

                city.DefaultView.RowFilter = "State=" + item [ "ID" ] ;

                return ;
            } ;

// Select the first State
            this.comboBox1.SelectedIndex = 0 ;

modified 14-Jan-13 9:49am.

a1_shay13-Jan-13 20:29

13-Jan-13 20:29

i have two DropDownList and i want that if i choose from the first DropDownList valu(i mean area) automaticly in the second DropDownList i will have all the cities in that area.

Mycroft Holmes13-Jan-13 21:06

Mycroft Holmes

13-Jan-13 21:06

Trap the change event on the 1st combo and filter the datasource of the second combo based on the selected item of the 1st combo.

Never underestimate the power of human stupidity
RAH

a1_shay13-Jan-13 21:08

13-Jan-13 21:08

How can I write this?

Mycroft Holmes13-Jan-13 23:58

Mycroft Holmes

13-Jan-13 23:58

By learning what an event is, how to wire it up and how to deal with the result. All this depends on your UI, ASP/SL-WPF/Winforms are all different.

Never underestimate the power of human stupidity
RAH

a1_shay14-Jan-13 0:53

14-Jan-13 0:53

someone already help me from anther site ,my problem now is only if i press on some button(even if the button do not doing anyting) i see the new data in my second DropDownList.how can i get the data Immediate in the second DropDownList when i change something in the first DropDownList ?

C++

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        DropDownList2.Items.Clear();
        string areaName = DropDownList1.Items[DropDownList1.SelectedIndex].ToString().Trim();
        DataRow[] city = dt.Select("area='" + areaName + "'");
        for (int i = 0; i < city.Count<DataRow>(); i++)
        {
            DropDownList2.Items.Add(city[i]["city_name"].ToString());
        }
    }

PIEBALDconsult14-Jan-13 3:05

PIEBALDconsult

14-Jan-13 3:05

Just set the DefaultView's RowFilter. Done.

modified 14-Jan-13 9:51am.

a1_shay14-Jan-13 3:08

14-Jan-13 3:08

i dont understand to what do you mean

PIEBALDconsult14-Jan-13 3:36

PIEBALDconsult

14-Jan-13 3:36

You have a DataTable with the cities, right? It has a DefaultView property. You set it as the DataSource of the control. Possibly have to set the DisplayMember property as well. And when the value in the other control changes, set the RowFilter value of this one.

a1_shay14-Jan-13 12:34

is it possible to work with Word files using Binary Reader and writer?

14-Jan-13 12:34

the solution was to change in the propoty of the first DropDownList the autopostback to true

hurrem13-Jan-13 5:41

hurrem

13-Jan-13 5:41

I need to translit the documents, translit from cyrillic letters to latin letters.
and I need to make my program to work with as many documents as it possible, and huge document, may be a document with 500 pages....
So, I'm thinking different ways to implement it to work as efficient as possible...
any advices?

Re: is it possible to work with Word files using Binary Reader and writer?

Garth J Lancaster13-Jan-13 10:19

Garth J Lancaster

13-Jan-13 10:19

I would have thought using Binary Reader and Writer would be extremely tortuous for this - you would have to parse the document file(s) by hand

Why not look at a level of abstraction 'above' that .. this is an interop/RCW method of interacting with a Word Doc ... http://code.msdn.microsoft.com/office/CSAutomateWord-f422cae5[^] but it may not be good for 500 pages - you'd have to loop through all pages getting the text, (possibly) creating a new document with the translated text.

There are other ways to read/write Word documents - Read Document Text Directly from Microsoft Word File[^] for instance

'g'

Deleting registry values

Erol230913-Jan-13 4:51

13-Jan-13 4:51

Hello,

My code is trying to delete IExplorer history from the registry! The typed URLs are stored in a checked listbox, i can delete one value at a time both in the registry and from the checked listbox but when i try deleting multiple items at a time it doesn't work? here is the code

private void Delete_Click(object sender, EventArgs e)
       {
           RegistryKey key = Registry.CurrentUser.OpenSubKey("Software\\Microsoft\\Internet Explorer\\TypedURLs", true);
           string[] v = key.GetValueNames();
           string[] t = new string[v.Length];
           int count = checkedListBox1.Items.Count;
           for (int i = 0; i < v.Length - 1; i++)
           {
               t[i] = (string)key.GetValue(v[i]);
               if(t[i] == (string)checkedListBox1.SelectedItem)
               {
                   key.DeleteValue(v[i]);
               }

           }

           for ( int i = count; i > 0; i--)
           {
               if (checkedListBox1.CheckedItems.Contains(checkedListBox1.Items[i - 1]))
               {

                   checkedListBox1.Items.RemoveAt(i - 1);
               }
           }




       }

Thomas Daniels13-Jan-13 6:06

Thomas Daniels

13-Jan-13 6:06

Hi,

if(t[i] == (string)checkedListBox1.SelectedItem)

SelectedItem is one item, use SelectedItems to get all selected items:

if (checkedListBox1.SelectedItems.Contains(t[i]))

Add also this in the constructor:

checkedListBox1.SelectionMode = SelectionMode.MultiExtended; // a user can select multiple items using the CTRL key, SHIFT key and the arrow keys
 // OR:
checkedListBox1.SelectionMode = SelectionMode.MultiSimple; // if a user clicked on a selected item in the list box, that item will be deselected, and if the user clicked on a deselected item in the list box, that item will be selected

Hope this helps.

In some cases, my signature will be longer than my message...

ASP

<em style="color:red"> <b>ProgramFOX</b></em>

ProgramFOX

modified 14-Jan-13 11:57am.

Erol230913-Jan-13 8:44

13-Jan-13 8:44

Still doesn't seem to have worked? Any other ideas please?

Thomas Daniels14-Jan-13 5:57

Thomas Daniels

14-Jan-13 5:57

Erol2309 wrote:
Any other ideas please?

I updated my answer.

In some cases, my signature will be longer than my message...

ASP

<em style="color:red"> <b>ProgramFOX</b></em>

ProgramFOX

Pete O'Hanlon13-Jan-13 8:56

Pete O'Hanlon

13-Jan-13 8:56

What does "doesn't work" mean? Ate you getting exceptions? What happens when you step over the code?

*pre-emptive celebratory nipple tassle jiggle* - Sean Ewington

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier

Erol230913-Jan-13 22:17

13-Jan-13 22:17

Well it means that when there are all the items in the checkedlistbox selected and i press the delete button they get deleted from the checkedlistbox but not from the registry...i cand only delete values from the registry one at a time and only when there are more than 2 entries..

Jibesh13-Jan-13 22:32

Jibesh

13-Jan-13 22:32

I Checked your code for deleting the multiple items from the registry and it works fine, if doesnt work means check the checkbox comparison operations.

Also I doubt on the action performed inside the second for loop, the checkBox content is checked against its own value was it v[i] or t[i] arrays?

Jibesh V P

Index was outside the bounds of the array.

Pete O'Hanlon13-Jan-13 23:40

Pete O'Hanlon

13-Jan-13 23:40

If you had stepped over your code, you would have seen what the problem is. Basically, you're iterating over one list of values, and you're getting one single value from the other list to compare it to. Try iterating over the selected items from the list box as well, and do your comparison in there.

Now, a more important point is that your comparison code is using terrible variable names. I ended up getting confused by your t and v variables.

*pre-emptive celebratory nipple tassle jiggle* - Sean Ewington

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier

Erol230913-Jan-13 4:11

Re: Index was outside the bounds of the array.

13-Jan-13 4:11

Hi,

I am trying to trite a small app that acceses internet browser history on IExplorer using its registry. Somehow i cannot delete the URLs that have been viewed.
note: After accesing the registry i store the data in a checkedlistbox. Any help?

private void Delete_Click(object sender, EventArgs e)
       {
           RegistryKey key = Registry.CurrentUser.OpenSubKey("Software\\Microsoft\\Internet Explorer\\TypedURLs", true);
           string[] v = key.GetValueNames();
           string[] t = new string[v.Length];
           int count = checkedListBox1.Items.Count;
           for (int i = 0; i < v.Length - 1; i--)
           {
               t[i] = (string)key.GetValue(v[i]);
               if(t[i] == (string)checkedListBox1.SelectedItem)
               {
                   key.DeleteValue(t[i]);
               }

           }

           for ( int i = count; i > 0; i--)
           {
               if (checkedListBox1.CheckedItems.Contains(checkedListBox1.Items[i - 1]))
               {

                   checkedListBox1.Items.RemoveAt(i - 1);
               }
           }

OriginalGriff13-Jan-13 4:15

OriginalGriff

13-Jan-13 4:15

Um:

for (int i = 0; i < v.Length - 1; i--)
{
    t[i] = (string)key.GetValue(v[i]);

i-- ? Really? Laugh | :laugh:

We all do it at some point... Blush | :O

If you get an email telling you that you can catch Swine Flu from tinned pork then just delete it. It's Spam.

Re: Index was outside the bounds of the array.

Erol230913-Jan-13 4:17