Winforms – Set value for same cell in “DevExpress XtraGrid CellValueChanging” event

devexpressgridviewwinforms

I have a XtraGrid with one GridView, with a column with checkbox repository item. Now I am handling the CellValueChanging event because I want to only allow the user to check or uncheck based on calculations on other column values on the same row hence I need the e.RowHandle and e.Column of this event and this cannot be done on the EditValueChanging of the repository control.

Now somewhere my calculations say that user cannot check a particular cell to and I throw a message box and try Me.BandedGridView1.SetRowCellValue(e.RowHandle, e.Column, False) but unfortunately this does not set the value to false of that cell.

I need to do it here and here only because of the huge number of calculations based on other column values and I need to set value of the current cell whose event I'm handling right.

Please help.

I'm using DevExpress 9.2 (no chance of upgrading to higher version)

Best Answer

Try this code it's working perfectly !

private void GridView1_CellValueChanged(object sender, CellValueChangedEventArgs e)
{
    if (e.Column.Caption != "yourColumnCaption") return;
       GridView1.SetFocusedRowCellValue("yourColumnFieldName", 1);
}

Related Solutions

C# – Cross-thread operation not valid: Control accessed from a thread other than the thread it was created on

As per Prerak K's update comment (since deleted):

I guess I have not presented the question properly.

Situation is this: I want to load data into a global variable based on the value of a control. I don't want to change the value of a control from the child thread. I'm not going to do it ever from a child thread.

So only accessing the value so that corresponding data can be fetched from the database.

The solution you want then should look like:

UserContrl1_LOadDataMethod()
{
    string name = "";
    if(textbox1.InvokeRequired)
    {
        textbox1.Invoke(new MethodInvoker(delegate { name = textbox1.text; }));
    }
    if(name == "MyName")
    {
        // do whatever
    }
}

Do your serious processing in the separate thread before you attempt to switch back to the control's thread. For example:

UserContrl1_LOadDataMethod()
{
    if(textbox1.text=="MyName") //<<======Now it wont give exception**
    {
        //Load data correspondin to "MyName"
        //Populate a globale variable List<string> which will be
        //bound to grid at some later stage
        if(InvokeRequired)
        {
            // after we've done all the processing, 
            this.Invoke(new MethodInvoker(delegate {
                // load the control with the appropriate data
            }));
            return;
        }
    }
}

.net – How to add a weighted average summary to a DevExpress XtraGrid

I ended up working this out, and will post my solution here in case others find it useful.

If a weighted average consists of both a value and a weight per row, then column that contains the value should have the weight GridColumn object assigned to its Tag property. Then, this event handler will do the rest:

private static void gridView_CustomSummaryCalculate(object sender, CustomSummaryEventArgs e)
{
    GridColumn weightColumn = ((GridSummaryItem)e.Item).Tag as GridColumn;

    if (weightColumn == null)
        return;

    switch (e.SummaryProcess)
    {
        case CustomSummaryProcess.Start:
        {
            e.TotalValue = new WeightedAverageCalculator();
            break;
        }
        case CustomSummaryProcess.Calculate:
        {
            double size = Convert.ToDouble(e.FieldValue);
            double weight = Convert.ToDouble(((GridView)sender).GetRowCellValue(e.RowHandle, weightColumn));

            ((WeightedAverageCalculator)e.TotalValue).Add(weight, size);
            break;
        }
        case CustomSummaryProcess.Finalize:
        {
            e.TotalValue = ((WeightedAverageCalculator)e.TotalValue).Value;
            break;
        }
    }
}

private sealed class WeightedAverageCalculator
{
    private double _sumOfProducts;
    private double _totalWeight;

    public void Add(double weight, double size)
    {
        _sumOfProducts += weight * size;
        _totalWeight += weight;
    }

    public double Value
    {
        get { return _totalWeight==0 ? 0 : _sumOfProducts / _totalWeight; }
    }
}

The code assumes that the underlying column values can be converted to doubles via Convert.ToDouble(object).

Best Answer

Related Solutions

C# – Cross-thread operation not valid: Control accessed from a thread other than the thread it was created on

.net – How to add a weighted average summary to a DevExpress XtraGrid

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