Multi Column Search In ListView ( C# ,Visual Studio 2015 )

Question

HI , I am using this code on OnKeyPress event , which filters my list View, but it only searches in the 1st Column of the List View .. Need Help ..
for  ( int  i = lv_panel_products.Items.Count - 1; i >= 0; i--)
{
ListViewItem lvi = lv_panel_products.Items[i];
foreach  (ListViewItem.ListViewSubItem subitem  in  lv_panel_products.Items)
{
if  (lvi.Text.ToLower().Contains(txt_searchproducts.Text.ToLower()) || subitem.Text.ToLower().Contains(txt_searchproducts.Text.ToLower()))
{
lvi.BackColor = Color.Black;
}
else
{
lv_panel_products.Items.Remove(lvi);
}
}
}

James Axsom · Answer

Hi Arslan. Here you go!   Code: namespace  SandBox   {           public  partial  class  MyMainForm : Form       {               // Class Constructor             public  MyMainForm()           {               InitializeComponent();           }               // Class Desconstructor            ~MyMainForm()           {              }               private   void  MyMainForm_Load( object  sender, EventArgs e)           {               PopulateListView( "CHE" ,  "Cherry" ,  "Small red sour tasting bulb with stem" ,  ".50/kg" );               PopulateListView( "LEM" ,  "Lemon" ,  "Yellow tart tasting fleshy fruit" ,  "1/kg" );               PopulateListView( "ORA" ,  "Orange" ,  "Orange sweet and juicy fruit" ,  "1.50/kg" );               PopulateListView( "APP" ,  "Apple" ,  "Apple is like a cherry. Red fleshy fruit of varying sizes and flavors" ,  "2.50/kg" );               PopulateListView( "BAN" ,  "Banana" ,  "Banana is same color as Lemon. Long fleshy sweet fruit that's smooshy" ,  ".50/kg" );               PopulateListView( "WAT" ,  "Watermelon" ,  "Big green fruit full of tasty chunky water" ,  ".50/kg" );           }               private   void  PopulateListView( string  id,  string  name,  string  description,  string  price)           {               ListViewItem fruit =  new  ListViewItem();               fruit.Text = id;                  ListViewItem.ListViewSubItem fruitName =  new  ListViewItem.ListViewSubItem();               fruitName.Text = name;               fruit.SubItems.Add(fruitName);                  ListViewItem.ListViewSubItem fruitDescription =  new  ListViewItem.ListViewSubItem();               fruitDescription.Text = description;               fruit.SubItems.Add(fruitDescription);                  ListViewItem.ListViewSubItem fruitPrice =  new  ListViewItem.ListViewSubItem();               fruitPrice.Text = price;               fruit.SubItems.Add(fruitPrice);                  lvwData.Items.Add(fruit);           }               private   void  btnSearch_Click( object  sender, EventArgs e)           {                string  criteria = txtCriteria.Text.Trim();                   foreach  (ListViewItem item  in  lvwData.Items)               {                    foreach  (ListViewItem.ListViewSubItem characteristic  in  item.SubItems)                   {                        if  (characteristic.Text.Contains(criteria) ==  true )                       {                           characteristic.BackColor = Color.CadetBlue;                       }                   }                      item.UseItemStyleForSubItems =  false ;               }                          }       }   }

James Axsom · Answer

My thinking is the variable "index", removes a listview item at that specific index in the control's items collection.   In a foreach loop the pointer variable cannot be used to remove an item from the collection during an foreach loop iteration. For example the following code will throw an error. item is the pointer for an item in the collection during an iteration. foreach (Object item  in  ListView.Items)   {        if (something ==  true )       {           ListView.Items.Remove(item);       }   }    On the other hand what if I didn't use item but instead used a counter variable index to count the number of iterations the foreach loop did and removed the listview item at that specific index without using the pointer variable, item. I have my doubts. I think it may still throw an error because because the collection is still in iteration at the sametime the request to remove an item is being made. That's my thinking.   So, the code isn't working. Is it not working because exceptions are being thrown? Its doing something but isn't doing what you think it should be doing?   From what I understand so far... 1) There is a database call. 2) The datatabe from the call is used and populates the listview control. 3) Criteria is offered. 4) Criteria is matched with all data in the rows and columns in the listview control. 5) Where the criteria matches, change that subitem's color to black   I'll upload a project independent from my code and your code. Once you download the project and run this project independently from your code in your project and see it working, then from there you can determine how to modify your code in order to change our listview subitems black.   Give me about a day or two and I'll upload a VS2017 project file.

James Axsom · Answer

Okay...

int index=0;
string criteria = txt_searchproducts.Text.ToLower();
foreach(ListViewItem item in lv_panel_products.Items)
{
foreach(ListViewItem.LIstViewItem.ListViewSubItem sitem in item.SubItems)
{
// each item (including the first at index 0) is a subitem
// no need to evaluate OR
if (sitem.Text.ToLower().Contains(criteria))
{
sitem.BackColor = Color.Black;
}
else
{
// this might cause a problem
// removing items from a collection during an iteration is problematic
lv_panel_products.Items.Remove(index);
}
index++;
}
item.UserItemsStyleForSubItems = false;
}

Arslan, my code and your code both iterate through items in a Listview control. It doesn’t matter how the list view is populated.

I’m going to break down your question word for word and interpret what you are requesting:

You said, “HI , I am using this code on OnKeyPress event , which filters my list View, but it only searches in the 1st Column of the List View .. Need Help “

If I had to rewrite your question, this would be my interpretation:

Key press event occurs and my listview filters on criteria. The criteria can be found on any row or in any column in the listview. The problem I’m encountering is the criteria only searches the 1^st column in the listview control and seems to ignore the other columns. It seems like it ignores the other columns because I know I have matching criteria in other rows and columns in my listview not just the first column. If the criteria matches then the listview item changes its color to black otherwise it removes the listview item from the list.

Arslan, I offer you a listview with data. I show you the criteria of lemon. Lemon can found in two different rows and in two different columns. I highlight the specific listview items where lemon is found.

I did this because your main objective is “Multi Column Search In ListView”

The key line of code is setting UseItemsStyleForSubItems = false on the listview item. If you don’t to this then none of the other columns (or subitems) will change their color to black.

The problem is a subitem does not have a UserItemsStyleForSubItems property only a listview item. Your code iterates through only subitems, which is in a way is accurate because when you get down to it, listview items are nothing more than a collection of subitems.

However, if you want to change your color to black, then you have iterate through a listview item and its subitems in two loops.

I'm not at my visual studio computer and I'm using an online editor for the code, but that the direction I would go.

Nitin Sontakke · Answer

@Arslan,   If you are just stuck at the deleting of the items, please remember that you should be traversing the list backwards, while deleting the items.   Our normal traversing from top to bottom modifies the index after deletion. This problem never occurs when you do it backwards.   Just the hint!

James Axsom · Answer

Project file attached: Screenshot:

Arslan Ali · Answer

Hi Once Again !    With All Your Help it is finding the elements , but the other thing i want to achieve is to delete those temporarily that do not match the search critera , do you have any idea how to achieve this , thank you !

Arslan Ali · Answer

Thanks For Helping Me Out ,  But Can You Please Explain Why Are You Using  index = 0; Where Are you Using The Index , Is It Necessary ?   The Code Is Not Running I Tried Several Different Things , And Also I Am Reloading The Products By Calling ViewProducts() Function :   Here    private   void  txt_searchproducts_TextChanged( object  sender, EventArgs e)         {              if  (txt_searchproducts.Text !=  "" )             {                     string  st = txt_searchproducts.Text.ToLower();                  foreach  (ListViewItem lvi  in  lv_panel_products.Items)                 {                          foreach  (ListViewItem.ListViewSubItem subitem  in  lvi.SubItems)                     {                             if  (subitem.Text.ToLower().Contains(st))                         {                             subitem.BackColor = Color.LightSteelBlue;                         }                          else                          {                             lv_panel_products.Items.Remove(lvi);                         }                     }                        lvi.UseItemStyleForSubItems =  false ;                 }                }              else              {                 lv_panel_products.Items.Clear();                 ViewProducts();             }               }

Arslan Ali · Answer

Thanks For Posting James , I Think I Should Explain More I Am Populating The ListView Using a Query To My Sql Server DB ,  Your Code Is Not Working Properly , May Be It Is Not Aligned With The One Using Database To Populate The LView, Rather Than Manually Entering Values Your Self , Can You Please Have A Look At my Code And Advice Where I Am Making A Mistake , Thanks Again !