how to get sum dynamically of datagridview column in textbox

Question

I want to get the sum of a column of datagridview and show that in textbox. After each entry the sum should be changed dynamically. For that I am using textChanged event of a textbox but when the entry is made it does not show any result. I want to get the result dynamically in the textbox. I want to avoid the use of button for sum.

Here is a piece of code for the textbox textChanged event:

private void textBox9_TextChanged(object sender, EventArgs e)
        {
            double sum = 0;
            for (int i = 0; i < dataGridView2.Rows.Count; ++i)
            {
                sum += Convert.ToDouble(dataGridView2.Rows[i].Cells[5].Value);
            }
            textBox9.Text = sum.ToString();
        }

Answer 1

You've got your code right, but instead I've put it in the CellValueChanged event and check to make sure it was the same cell you're looking for. This will get fired if the cell's value changes, or if a new row is added and subsequently gets a value assigned.

    private void dataGridView2_CellValueChanged(object sender, DataGridViewCellEventArgs e)
    {
        if (e.ColumnIndex == 5)
            textBox9.Text = CellSum().ToString();
    }

    private double CellSum()
    {
        double sum = 0;
        for (int i = 0; i < dataGridView2.Rows.Count; ++i)
        {
            double d = 0;
            Double.TryParse(dataGridView2.Rows[i].Cells[5].Value.ToString(), out d);
            sum += d;
        }
        return sum;
    }

I split up your logic into a separate method, so incase you ever want to get the sum for something else, you can simply call that method. I suppose you could just read textbox.Text, but...

I've also used Double.TryParse as it provides some basic protection incase the value in that given cell is not actually a number. I don't know what the source of the data is (user entered / from an outside source?) so I figured I'd add a little protection.

Edit Grant raises a great point, editted my solution to include cell value being modified. I used the CellValueChanged event instead of CellEndEdit, incase something other than the user can change its value.

Answer 2

this is the best simple way :

private void your_name()
{

    Double your_variable = dataGridView1.Rows.Cast<DataGridViewRow>().Sum(x => Convert.ToDouble(x.Cells["Column4"].Value));

    this.textBox1.Text = your_variable.ToString("N2");
}

Answer 3

If you need to take into account the possibility that a user may edit existing values in the grid rows, you can subscribe to the CellEndEdit event.

Here, I'm checking the column index so you're not recalculating the sum if any other unrelated columns are edited. (I'm also validating the input and setting the value to 0 if, say, someone enters letters.)

private void dataGridView1_CellEndEdit(object sender, DataGridViewCellEventArgs e)
{
    if (e.ColumnIndex == 5)
    {
        decimal result;
        if (!Decimal.TryParse(Convert.ToString(dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value), out result))
            dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value = 0;

        textBox1.Text = dataGridView1.Rows.Cast<DataGridViewRow>()
                                     .Sum(x => Convert.ToDecimal(x.Cells[5].Value))
                                     .ToString();
    }
}

Others may have better solutions... this is just one possibility.

Answer 4

private void dataGridView2_CellEndEdit(object sender, DataGridViewCellEventArgs e)
    {
        if (e.ColumnIndex == 5)
        {
            summition();
        }
    }
    void summition() 
    { 
        double sum = 0;
        foreach (DataGridViewRow row in dataGridView2.Rows)
        {
            if(!row .IsNewRow )
                sum += Convert.ToDouble(row.Cells [5].Value .ToString () );
        }


        textBox9.Text = sum.ToString();
    }

Answer 5

You have to handle the event CellValueChanged. However your approach is a little bad because each time a cell's value changes, you have to loop through all the rows to update the sum. You should track your cell change to store the last value, then you can update the sum easily. The sum needs to be calculated initially using the loop. It's just done 1 time.

//This is used as CellTemplate for your interested column
public class TrackedValueDataGridViewCell : DataGridViewTextBoxCell {
    public object OldValue { get; set; }
    protected override bool SetValue(int rowIndex, object value) {
      OldValue = Value;                
      return base.SetValue(rowIndex, value);
    }
}

public partial class Form1 : Form {
  public Form1(){
    InitializeComponent();
    //init your grid
    dataGridView1.DataSource = yourDataSource;
    dataGridView1.Columns["sumColumn"].CellTemplate = new TrackedValueDataGridViewCell();
    sum = InitSum(dataGridView1,"sumColumn");
    textBox9.Text = sum.ToString();
    dataGridView1.CellValueChanged += (s,e) => {
      if(dataGridView1.Columns[e.ColumnIndex].Name != "sumColumn") return;
      var cell = ((TrackedValueDataGridViewCell) dataGridView1[e.ColumnIndex, e.RowIndex]);
      sum -= ((double?) cell.OldValue).GetValueOrDefault();
      sum += ((double?)cell.Value).GetValueOrDefault();
      textBox9.Text = sum.ToString();
    };

  }
  double sum;
  public double InitSum(DataGridView grid, string colName) {
      return grid.Rows.OfType<DataGridViewRow>()                       
                 .Sum(row => ((double?) row.Cells[colName].Value).GetValueOrDefault());
  }
}

NOTE: I suppose the column you want to sum up is named sumColumn, we should use Name to reference column because it's more readable. The code above doesn't count the cases when adding new rows and removing existing rows from grid. In fact, whenever adding and removing programmatically, you should update the sum easily right before adding and removing. For adding we can handle the RowsAdded event. All the following event handler registrations should be placed in some Form.Load event handler:

dataGridView1.RowsAdded += (s, e) => {
    for (int i = e.RowIndex; i < e.RowIndex + e.RowCount; i++) {
        sum += ((double?)dataGridView1["sumColumn", i].Value).GetValueOrDefault();
    }
    textBox9.Text = sum.ToString();
};

However for removing rows, it's very tricky. The RowsRemoved doesn't work well, we can't refer the removed rows anymore in the RowsRemoved event handler, so we may have to loop through all the rows and update the sum:

dataGridView1.RowsRemoved += (s, e) => {
  sum = InitSum(dataGridView1,"sumColumn");
  textBox9.Text = sum.ToString();      
};

That's for removing rows by both code and user. Another option which is better is you have to handle the UserDeletingRow (but this works only for removing rows by user, not by code). To handle removing rows by code, I think you can always insert code updating the sum before any code removing the rows, here it is:

//for user removing rows
dataGridView1.UserDeletingRow += (s, e) => {
  sum -= ((double?) e.Row.Cells["sumColumn"].Value).GetValueOrDefault();
  textBox9.Text = sum.ToString();
};
//for code removing rows, use some method to remove rows like this:
public void RemoveRows(DataGridView grid, int startIndex, int count){
  for(int i = startIndex; i <= startIndex + count; i++){
     //update the sum first
     sum -= ((double?)grid.Rows[i].Cells["sumColumn"].Value).GetValueOrDefault();
     //then remove the row
     grid.Rows.RemoveAt(startIndex);
  }
  textBox9.Text = sum.ToString();
}

Note that all the event handlers should be registered after your grid has been initialized with some initial data following by the sum initialization.