You can have one event for all as below, you can select the combo box on designer and go to events and select
ComboBoxSelectedIndexChanged
as
SelectedIndexChanged
event.
Note that you can cast sender as ComboBox and get text.
private void ComboBoxSelectedIndexChanged(object sender, EventArgs e)
{
ComboBox comboBox = (ComboBox) sender;
for (int i = 0; i < datagridviewserach.Columns.Count; i++)
{
for (int j = 0; j < datagridviewserach.Rows.Count; j++)
{
if (datagridviewserach[i, j].Value != null)
{
if (datagridviewserach[i, j].Value.ToString() == comboBox.Text)
{
datagridviewserach[i, j].Style.BackColor = Color.Blue;
datagridviewserach.Rows[j].DefaultCellStyle.BackColor = Color.Red;
}
else datagridviewserach[i, j].Style.BackColor = Color.White;
}
}
}
}