DataTable.Columns.Add()时,提示“未处理NullReferenceException,未将对象引用设置到对象实例”~求指导,急~
private void button1_Click(object sender, EventArgs e)
{
DataTable dt = new DataTable();
dt = null;
DataRow dr = null;
for (int i = 0; i < lv1.Columns.Count; i++)
{
dt.Columns.Add(lv1.Columns[i].Text, typeof(string));
}
运行时提示“未处理NullReferenceException,未将对象引用设置到对象实例”
拜托了~急~~