You can try this one.
var dictionary = new Dictionary<string, int>();
dictionary.Add("pay_month", 2);
dictionary.Add("pay_year", 1);
if (dt.Rows.Count > 0)
{
DataRow row = dt.Rows[0];
row["Month"]=dictionary["pay_month"];
row["year"]=dictionary["pay_year"];
}
solved C#-How to update a first row in DataTable based on dictionary values [closed]