string connection = "server=.;database=mydb;user id=sa;pwd=123";
SqlConnection myconnection = new SqlConnection(connection);
SqlDataAdapter sql = new SqlDataAdapter();
sql.SelectCommand.CommandText = "Select 学生号,姓名,年龄,性别 from 学生表";
DataSet set = new DataSet();
sql.Fill(set, "学生表");
dataGridView1.DataSource = set.Tables["学生表"];
SqlConnection myconnection = new SqlConnection(connection);
SqlDataAdapter sql = new SqlDataAdapter();
sql.SelectCommand.CommandText = "Select 学生号,姓名,年龄,性别 from 学生表";
DataSet set = new DataSet();
sql.Fill(set, "学生表");
dataGridView1.DataSource = set.Tables["学生表"];
下断点,看set.Tables["学生表"]是否存在。
string s = textBox1.Text; string connection = "server=.;database=mydb;user id=sa;pwd=123";
SqlConnection myconnection = new SqlConnection(connection);
SqlDataAdapter sql = new SqlDataAdapter();
sql.SelectCommand = new SqlCommand("Select 学生号,姓名,年龄,性别 from 学生表 where 学生号='" + s + "'", myconnection);
n = sql.Fill(set, "学生表");
dataGridView1.DataSource = set.Tables["学生表"];
if (n == 0)
{ MessageBox.Show("输入有误", "请重新输入"); }为什么会执行 MessageBox.Show("输入有误", "请重新输入");?
其他链接都对了~
SqlConnection myconnection = new SqlConnection(connection);
SqlDataAdapter sql = new SqlDataAdapter();
sql.SelectCommand = new SqlCommand("Select 学生号,姓名,年龄,性别 from 学生表 where 学生号='" + s + "'", myconnection);
n = sql.Fill(set, "学生表");
dataGridView1.DataSource = set.Tables["学生表"];
if (n == 0)
{ MessageBox.Show("输入有误", "请重新输入"); }为什么在dataGridView1 显示不出?
其他链接都对了~
string sqlstr="Select 学生号,姓名,年龄,性别 from 学生表 where 学生号='" + s + "'";
sql.SelectCommand = new SqlCommand(sqlstr,myconnection);
这个下面加一句
dataGridView1.DataBind();
下面加一句
dataGridView1.DataBind();
string connection = "server=.;database=mydb;user id=sa;pwd=123";
SqlConnection myconnection = new SqlConnection(connection);
string sql = "Select 学生号,姓名,年龄,性别 from 学生表";
SqlDataAdapter sql = new SqlDataAdapter(sql,con);
DataSet set = new DataSet();
sql.Fill(set, "学生表");
dataGridView1.DataSource = set.Tables["学生表"];
SqlConnection myconnection = new SqlConnection(connection);
con.open();
string sql = "Select 学生号,姓名,年龄,性别 from 学生表";
SqlDataAdapter sda = new SqlDataAdapter(sql,con);
DataSet ds= new DataSet();
sda.Fill(ds, "学生表");
dataGridView1.DataSource = ds.Tables["学生表"];
string s = textBox1.Text; string connection = "server=.;database=mydb;user id=sa;pwd=123";
SqlConnection myconnection = new SqlConnection(connection);
SqlDataAdapter sql = new SqlDataAdapter();
sql.SelectCommand = new SqlCommand("Select 学生号,姓名,年龄,性别 from 学生表 where 学生号='" + s + "'", myconnection);
n = sql.Fill(set, "学生表");
if(set.Tables["学生表"].Rows.Count < 1)
{
MessageBox.Show("木有数据");
return;
}
dataGridView1.DataSource = set.Tables["学生表"];
if (n == 0)
{ MessageBox.Show("输入有误", "请重新输入"); }
谢谢楼上几位~
StringBuilder sb=new StringBuilder();string sql =@"delete from 学生表 where 1=1 ";
if(textBox7.Text!="")
sb.Append("and 学生号='" + textBox7.Text + "'");
if(textBox8.Text!="")
sb.Append("and 姓名='" + textBox8.Text + "'");
if(textBox9.Text!="")
sb.Append("and 年龄='" + textBox9.Text + "'");
if(textBox10.Text!="")
sb.Append("and 性别='" + textBox10.Text + "'");
sql=sql+sb.ToString();