Question

c# 中数据库查询问题（判断为空）

以下是代码：

string strConn = "server=.;database=mydb;uid=sa;pwd=sa";
SqlConnection myConnection = new SqlConnection(strConn);
myConnection.Open();
DataSet myDataset = new DataSet();
string i = this.TextBox1.Text;
string sqlText = "select *from person where id="+i;
SqlDataAdapter myDataAdapter = new SqlDataAdapter(sqlText, myConnection);
myDataAdapter.Fill(myDataset);

///想在这里加个判断，查询内容不未空是才显示到grieview中

this.GridView1.DataSource = myDataset;
this.GridView1.DataBind();

Answer 1

string strConn = "server=.;database=mydb;uid=sa;pwd=sa";
SqlConnection myConnection = new SqlConnection(strConn);
myConnection.Open();
DataTable dt= new DataTable();
string i = this.TextBox1.Text;
string sqlText = "select *from person where id="+i;
SqlDataAdapter myDataAdapter = new SqlDataAdapter(sqlText, myConnection);
myDataAdapter.Fill(dt);

this.GridView1.DataSource = dt;
this.GridView1.DataBind();

if(dt.rows.count<=0)
{
//提示消息，数据不存在。
}

Answer 2

if(myDataset.Tables[0].Rows.Count == 0){ //这个myDataset为空}