Asked  7 Months ago    Answers:  5   Viewed   100 times

I'm developing user control in C# Visual Studio 2010 - a kind of "quick find" textbox for filtering datagridview. It should work for 3 types of datagridview datasources: DataTable, DataBinding and DataSet. My problem is with filtering DataTable from DataSet object, which is displayed on DataGridView.

There could be 3 cases (examples for standard WinForm application with DataGridView and TextBox on it) - first 2 are working OK, I've problem with 3rd one:

1. datagridview.DataSource = dataTable : it works
so I can filter by setting: dataTable.DefaultView.RowFilter = "country LIKE '%s%'";

DataTable dt = new DataTable();

private void Form1_Load(object sender, EventArgs e)
{
    dt.Columns.Add("id", typeof(int));
    dt.Columns.Add("country", typeof(string));

    dt.Rows.Add(new object[] { 1, "Belgium" });
    dt.Rows.Add(new object[] { 2, "France" });
    dt.Rows.Add(new object[] { 3, "Germany" });
    dt.Rows.Add(new object[] { 4, "Spain" });
    dt.Rows.Add(new object[] { 5, "Switzerland" });
    dt.Rows.Add(new object[] { 6, "United Kingdom" });

    dataGridView1.DataSource = dt;
}

private void textBox1_TextChanged(object sender, EventArgs e)
{
    MessageBox.Show("DataSource type BEFORE = " + dataGridView1.DataSource.GetType().ToString());

    dt.DefaultView.RowFilter = string.Format("country LIKE '%{0}%'", textBox1.Text);

    MessageBox.Show("DataSource type AFTER = " + dataGridView1.DataSource.GetType().ToString());
} 

2. datagridview.DataSource = bindingSource: it works
so I can filter by setting: bindingSource.Filter = "country LIKE '%s%'";

DataTable dt = new DataTable();
BindingSource bs = new BindingSource();

private void Form1_Load(object sender, EventArgs e)
{
    dt.Columns.Add("id", typeof(int));
    dt.Columns.Add("country", typeof(string));

    dt.Rows.Add(new object[] { 1, "Belgium" });
    dt.Rows.Add(new object[] { 2, "France" });
    dt.Rows.Add(new object[] { 3, "Germany" });
    dt.Rows.Add(new object[] { 4, "Spain" });
    dt.Rows.Add(new object[] { 5, "Switzerland" });
    dt.Rows.Add(new object[] { 6, "United Kingdom" });

    bs.DataSource = dt;
    dataGridView1.DataSource = bs;
}

private void textBox1_TextChanged(object sender, EventArgs e)
{
    MessageBox.Show("DataSource type BEFORE = " + dataGridView1.DataSource.GetType().ToString());

    bs.Filter = string.Format("country LIKE '%{0}%'", textBox1.Text);

    MessageBox.Show("DataSource type AFTER = " + dataGridView1.DataSource.GetType().ToString());
}

3. datagridview.DataSource = dataSource; datagridview.DataMember = "TableName": it doesn't work
It happens when you design a table using designer: put the DataSet from toolbox on form, add dataTable to it and then set datagridview.DataSource = dataSource; and datagridview.DataMember = "TableName".
Code below pretends these operations:

DataSet ds = new DataSet();
DataTable dt = new DataTable();

private void Form1_Load(object sender, EventArgs e)
{
    dt.Columns.Add("id", typeof(int));
    dt.Columns.Add("country", typeof(string));

    dt.Rows.Add(new object[] { 1, "Belgium" });
    dt.Rows.Add(new object[] { 2, "France" });
    dt.Rows.Add(new object[] { 3, "Germany" });
    dt.Rows.Add(new object[] { 4, "Spain" });
    dt.Rows.Add(new object[] { 5, "Switzerland" });
    dt.Rows.Add(new object[] { 6, "United Kingdom" });

    ds.Tables.Add(dt);
    dataGridView1.DataSource = ds;
    dataGridView1.DataMember = dt.TableName;
}

private void textBox1_TextChanged(object sender, EventArgs e)
{
    MessageBox.Show("DataSource type BEFORE = " + dataGridView1.DataSource.GetType().ToString());  
    //it is not working
    ds.Tables[0].DefaultView.RowFilter = string.Format("country LIKE '%{0}%'", textBox1.Text);

    MessageBox.Show("DataSource type AFTER = " + dataGridView1.DataSource.GetType().ToString());
}

If you test it - although datatable is filtered (ds.Tables[0].DefaultView.Count changes), datagridview is not updated... I've been looking for a long time for any solution, but the problem is that DataSource cannot change - as it's additional control, I don't want it to mess up with programmer's code.

I know possible solutions are:
- to bind DataTable from DataSet using DataBinding and use it as example 2: but it's up to the programmer during code writing,
- to change dataSource to BindingSource, dataGridView.DataSource = dataSet.Tables[0], or to DefaultView programatically: however, it changes the DataSource. So the solution:

private void textBox1_TextChanged(object sender, EventArgs e)
{
    MessageBox.Show("DataSource type BEFORE = " + dataGridView1.DataSource.GetType().ToString(), ds.Tables[0].DefaultView.Count.ToString());

    DataView dv = ds.Tables[0].DefaultView;
    dv.RowFilter = string.Format("country LIKE '%{0}%'", textBox1.Text);
    dataGridView1.DataSource = dv;

    MessageBox.Show("DataSource type AFTER = " + dataGridView1.DataSource.GetType().ToString(), ds.Tables[0].DefaultView.Count.ToString());
}

is not acceptable, as you see on MessageBox's dataSource is changing...

I don't want to do that, because it's possible a programmer writes code similar to this:

private void textBox1_TextChanged(object sender, EventArgs e)
{
    MessageBox.Show("DataSource type BEFORE = " + dataGridView1.DataSource.GetType().ToString(), ds.Tables[0].DefaultView.Count.ToString());

    DataSet dsTmp = (DataSet)(dataGridView1.DataSource);   //<--- it is OK 

    DataView dv = ds.Tables[0].DefaultView;
    dv.RowFilter = string.Format("country LIKE '%{0}%'", textBox1.Text);
    dataGridView1.DataSource = dv;   //<--- here the source is changeing from DataSet to DataView

    MessageBox.Show("DataSource type AFTER = " + dataGridView1.DataSource.GetType().ToString(), ds.Tables[0].DefaultView.Count.ToString());

    dsTmp = (DataSet)(dataGridView1.DataSource);    //<-- throws an exception: Unable to cast object DataView to DataSet
}

He can do that, as he designed DataGridView with DataSet and DataMember in designer. Code will be compiled, however, after using a filter, it will throw an exception...

So the question is: how can I filter DataTable in DataSet and show the results on DataGridView without changing DataSource to another? Why I can filter DataTable from example 1 directly, while filtering DataTable from DataSet is not working? Maybe it's not DataTable bound to DataGridView in that case?

Please note, that my problem takes from designing issues, so the solution MUST WORK on example 3.

 Answers

75

I just spent an hour on a similar problem. For me the answer turned out to be embarrassingly simple.

(dataGridViewFields.DataSource as DataTable).DefaultView.RowFilter = string.Format("Field = '{0}'", textBoxFilter.Text);
Tuesday, June 1, 2021
 
StampyCode
answered 7 Months ago
36

The CellValidating event occurs just prior to when the DataGridView leaves edit mode; it's an event that relates-to/involves the editing control (DataGridView.EditingControl). You should never attempt to change the cell value in the handler for this event, because unless you cancel the event (in which case the user is stuck in edit mode), the cell value is set to the value from the editing control immediately after the event finishes. This, therefore, undoes any action you perform in the handler.

What you have to do instead is change the value in the editing control (remembering not to cancel the event). For example, for a DataGridViewTextBoxCell, you would use the following instead of your problematic line:

unit_List_2_GroupsDataGridView.EditingControl.Text = Convert.ToString(rows[0]["Batch"]);

You should find that this solves your issue.

Monday, August 2, 2021
 
Ula
answered 4 Months ago
Ula
18

I suppose if you just wanted to represent the contents of the cells as text and copy them to the clipboard, tab-delimited, you could do something like:

    var newline = System.Environment.NewLine;
    var tab = "t";
    var clipboard_string = "";

    foreach (DataGridViewRow row in dataGridView1.Rows)
    {
         for (int i=0; i < row.Cells.Count; i++)
         {
              if(i == (row.Cells.Count - 1))
                   clipboard_string += row.Cells[i].Value + newline;
              else
                   clipboard_string += row.Cells[i].Value + tab;
         }
    }

    Clipboard.SetText(clipboard_string);

The output seems pretty similar to that of the GetClipboardContent(), but be careful for any DataGridViewImageColumns or any type that isn't implicitly a string.

Edit: Anthony is correct, use StringBuilder to avoid allocating a new string for every concatenation. The new code:

    var newline = System.Environment.NewLine;
    var tab = "t";
    var clipboard_string = new StringBuilder();

    foreach (DataGridViewRow row in dataGridView1.Rows)
    {
        for (int i = 0; i < row.Cells.Count; i++)
        {
            if (i == (row.Cells.Count - 1))
                clipboard_string.Append(row.Cells[i].Value + newline);
            else
                clipboard_string.Append(row.Cells[i].Value + tab);
        }
    }

    Clipboard.SetText(clipboard_string.ToString());
Thursday, August 12, 2021
 
PandemoniumSyndicate
answered 4 Months ago
95

Paste this code into your form classes:

    protected override void OnFormClosing(FormClosingEventArgs e) {
        e.Cancel = false;
        base.OnFormClosing(e);
    }

When that works, you want to find out why you have Validating event handlers that don't want the form to be closed.

Next thing you want to verify is Debug + Exceptions, tick the Thrown box for CLR Exceptions. This makes sure you don't swallow an exception that prevents a form from closing. Or worse, the operating system swallowing the exception, a nasty Windows 7 problem.

Wednesday, August 18, 2021
 
Fostah
answered 4 Months ago
78

You can use a BindingSource to bind your datasource to your DataGridView. This way you only change the Filter property of your bindingSource and the filter automatically will apply to data shown in the grid. No need to change datasource.

Sunday, August 29, 2021
 
Wijden
answered 3 Months ago
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