C#winform，查询sql数据库并显示在datagridview里

小弟最近在自学C#，然后现在自己琢磨着做个小的查询系统，大概如图
现在的问题就是，选择了查询方式之后，查询并不显示数据，分布运行也没有报错，大侠们来帮看看~
下边是查询button代码
private void button1_Click(object sender, EventArgs e)
{
SqlConnection conn = new SqlConnection();
conn.ConnectionString = "Data Source=LENOVO-PC;Initial Catalog=Passenger;Integrated Security=True";
conn.Open();
if (radioButton1.Checked == true)
{
DateTime.Now.ToString("yyyy-MM-dd");
DateTime dt0 = DateTime.Now;
SqlDataAdapter sda = new SqlDataAdapter("select * from SecurityCheck where InspectionBegin = '"+dt0+"'", conn);
DataSet ds = new DataSet();
sda.Fill(ds);
dataGridView1.DataSource = ds;
}
if (radioButton2.Checked == true)
{
System.DateTime currentTime = new System.DateTime();
int 时 = currentTime.Hour;
int 分 = currentTime.Minute;
int 秒 = currentTime.Second;
DateTime.Now.ToString("yyyy-MM-dd HH:MM:SS");
DateTime dt0 = DateTime.Now;
DateTime dt1 = dt0.AddHours(-2.0);
SqlDataAdapter sda = new SqlDataAdapter("select * from SecurityCheck where InspectionBegin = '"+dt1+"' ",conn);
DataSet ds = new DataSet();
sda.Fill(ds);
dataGridView1.DataSource = ds;
}
if (radioButton3.Checked == true)
{
SqlDataAdapter sda = new SqlDataAdapter("select * from SecurityCheck where InspectionBegin='"+dateTimePicker1.Text+"'and InspectionOut='"+dateTimePicker2.Text+"'", conn);
DataSet ds = new DataSet();
sda.Fill(ds);
dataGridView1.DataSource = ds;
}
conn.Close();
}