How to change DataGridView cell color based on val

问题:

I have a datagridview as below:

I would like:

• When the form load, if the Gender column's value is Male, the corresponding color cell of column Name will be White

• When if changes the value of the column Gender: Male → Female, color cell of the column Name will be DarkGray, otherwise if changes the value of the column Gender: Female → Male, color cell of the column Name will be White

I tried it but I am not able to do it:

    private void dataGridView_CurrentCellDirtyStateChanged(object sender, EventArgs e)
    {
        DataGridView dgv = sender as DataGridView;
        DataGridViewCell cell = dgv.CurrentCell;

        if (dgv.Rows[cell.RowIndex].Cells["Gender"].Value.ToString().Trim() == "Male")
        {
            // Male
            dgv.Rows[cell.RowIndex].DefaultCellStyle.BackColor = Color.White;
        }
        else
        {
            // Female
            dgv.Rows[cell.RowIndex].DefaultCellStyle.BackColor = Color.DarkGray;
        }
    }

OR:

    private void dataGridView_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
    {
        DataGridView dgv = sender as DataGridView;

        if (dgv.Columns[e.ColumnIndex].Name.Equals("Gender"))
        {
            if (e.Value != null && e.Value.ToString().Trim() == "Male")
            {
                e.CellStyle.BackColor = Color.White;
            }
            else
            {
                e.CellStyle.BackColor = Color.DarkGray;
            }
        }

        //if (dgv.Rows[e.RowIndex].Cells["Gender"].Value.ToString().Trim() == "Male")
        //{
        //    e.CellStyle.BackColor = Color.White;
        //}
        //else
        //{
        //    e.CellStyle.BackColor = Color.DarkGray;
        //}
    }

Any tips on these will be great help. Thanks in advance.

回答1:

To change the Background color you must subscribe to the CellFormatting event. Then add this code to the event handler:

private void dataGridView_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
{
    DataGridView dgv = sender as DataGridView;

    if (dgv.Columns[e.ColumnIndex].Name.Equals("Gender"))
    {
        if (e.Value != null && e.Value.ToString().Trim() == "Male")
        {
            dgv.Rows[e.RowIndex].Cells["name"].Style.BackColor = Color.White;
        }
        else
        {
            dgv.Rows[e.RowIndex].Cells["name"].Style.BackColor = Color.DarkGray;
        }
    }

}

To cause a validation when a new value is selected in your DataGridViewComboBoxCell,subscribe to the CurrentCellDirtyStateChanged event and try this code in its handler:

private void dataGridView_CurrentCellDirtyStateChanged(object sender, EventArgs e)
{
    DataGridView dgv = sender as DataGridView;
    DataGridViewCell cell = dgv.CurrentCell;
    if (cell is DataGridViewComboBoxCell)
    {
        dgv.CommitEdit(DataGridViewDataErrorContexts.Commit);
        dgv.EndEdit();
    }
}

回答2:

Just to show you a working example, I am changing ForeColor instead of Back, but the concept is the same. You need to apply a default:

this.dgvUsers.DefaultCellStyle.ForeColor = Color.Black;

Then based on what your trigger is, you need to assign a handler:

dgvUsers.CellFormatting += new System.Windows.Forms.DataGridViewCellFormattingEventHandler(this.dgvUsers_CellFormatting);
this.Controls.Add(dgvUsers);

Then to handle the event, it will look something like this:

// Handle user going inactive or being reactivated
private void dgvUsers_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
{
    DataRowView row = dgvUsers.Rows[e.RowIndex].DataBoundItem as DataRowView;
    if (row != null && row.Row.ItemArray[7].Equals("N"))
    {
        e.CellStyle.ForeColor = Color.Gray;
    }
    else
    {
        e.CellStyle.ForeColor = Color.Black;
    }
}

Unlike the accepted answer, this uses styles to have to change defined in a single place.