How to create filtering for DataTable based on toggle switches?

[Alex Dunlop]

Hi, I have 15 toggle switches in my project (Using DevExpress). All of them are related to column 2 of the DataTable and are used for filtering. I want to filter the DataTable based on those toggle switches the user turns on. I don't know what algorithm should I use to set my filtering and cover all the toggle switches that are on.

DataView dv = new DataView(my_table3);
dv.RowFilter = $"Column2 = '{checked_item2[0]}' OR Column2 = '{checked_item2[1]}' OR Column2 = '{checked_item2[2]}'";

[OriginalGriff]

I don't think string interpolation will work there: interpolated strings are a syntactic sugar for the older method using numbered parameters and are evaluated when the interpolated string is constructed, not when it is used:

using System;

public class Program
{
static string name = "???";
static string xxx = $"Hello {name}!";
static string yyy = "Hello {0}!";
public static void Main()
{
name = "Paul";
Console.WriteLine($"Hello {name}!");
Console.WriteLine(xxx);
Console.WriteLine(yyy, name);
}
}

Will give you:

Hello Paul!
Hello ???!
Hello Paul!

So setting a RowFilter to the value of a variable doesn't mean that it will change the View at all whcn checks change: it will only use the values at the moment when the string is created. What you need to do is change the filter each time the user changes the check boxes.

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony "Common sense is so rare these days, it should be classified as a super power" - Random T-shirt AntiTwitter: @DalekDave is now a follower!

[Alex Dunlop]

This filter is a part of a bigger calculations. I export a huge Excel file into DataTable and filter rows based I toggle switches and continue the calculations. This process is done when the user clicks a button. So I don't need to have synchronous filtering. My problem is that I don't know how many toggle switches will be on to set them in my Filter String. Please guide me.

[OriginalGriff]

If you don't know, then you need to process them. Create a List<string> and loop through your switches: if it's set, add the condition string to the collection:

if (myCheck.Checked)
{
myList.Add($"Column2 = '{checked_item2[n]}'");
}

Then when you have them all, use string.Join[^] with a separator of " OR " to produce your filter.

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony "Common sense is so rare these days, it should be classified as a super power" - Random T-shirt AntiTwitter: @DalekDave is now a follower!

[jsc42]

Might be slightly more compact to do

Column2 IN ('{checked_item2.Join("', '")}')"

this would also be impervious to changing the no of checkboxes I've not tested this. I am assuming that the filter texts are fixed (i.e. the user cannot change them). Also beware if any values have an ' in them - the ' have to be doubled.

[Alex Dunlop]

How can I join List<> elements parametrically? For example I don't know the count of checked toggle switches at first but during the process I find out that n = 5. Sting.Join(" OR ", checked_item2[0], .....);

[OriginalGriff]

String.Join accepts any IEnumerable - including a List - so read what I said, and give it a try. To do it with parameters would mean knowing what your user was going to select at compile time ...

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony "Common sense is so rare these days, it should be classified as a super power" - Random T-shirt AntiTwitter: @DalekDave is now a follower!

[Alex Dunlop]

I tried this:

foreach (BarItem c in ribbonControl1.Items)
{
if (c is BarToggleSwitchItem tg2 && tg2.Checked)
{
if (tg2.Description == "text1" || tg2.Description == "text2" || tg2.Description == "text3" ||
tg2.Description == "text4" || tg2.Description == "text5" || tg2.Description == "text6")
{

                    checked\_item2.Add(tg2.Description);
                    checkedIndex2.Add($"Column15 = '{checked\_item2\[n\]}'");
                    n++;
                }
            }
        }

And:

string filterString;
filterString= string.Join(" OR ", checked_item2[0]);//The problem is here. I don't know how many times I need to write checked_item2[1,2...,n]

I don't know how many times I need to write checked_item2[1,2...,n]

[Alex Dunlop]

I used your algorithm and it solved my problem. Now, I want to deliver the filtered table into a new DataTable. I used this:

DataTable filteredTable = dv.ToTable();//dv is DataView

When I debug the code, there is some information in dv table but filteredTable is empty. Why?

[OriginalGriff]

Firstly, a DataView isn't a table - it is a filtered view of a table and that's quite different in reality. Secondly, it works fine for me:

    private void TwoDGVs\_Shown(object sender, EventArgs e)
        {
        string strConnect = SMDBSupport.SMInstanceStorage.GetInstanceConnectionString(DBName);
        DataTable dt = new DataTable();
        using (SqlConnection con = new SqlConnection(strConnect))
            {
            try
                {
                con.Open();
                using (SqlDataAdapter da = new SqlDataAdapter("SELECT \* FROM MyTable", con))
                    {
                    da.SelectCommand.Parameters.AddWithValue("@SEARCH", "The text to search for");
                    da.Fill(dt);
                    }
                }
            catch (Exception ex)
                {
                Debug.WriteLine(ex.ToString());
                }
            }
        DataView dv = new DataView(dt);
        Source.DataSource = dv;
        }

    private void Filter\_TextChanged(object sender, EventArgs e)
        {
        if (Source.DataSource is DataView dv)
            {
            dv.RowFilter = $"Title LIKE '%{Filter.Text}%'";
            DataTable dt = dv.ToTable();
            Destination.DataSource = dt;
            }
        }

I get two DGV's, one looking a all rows, the other filtered.

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony "Common sense is so rare these days, it should be classified as a super power" - Random T-shirt AntiTwitter: @DalekDave is now a follower!