Cannot implicitly convert type 'System.Data.IDataReader' to 'System.Data.SqlClient.SqlDataReader'

Question

User221424154 posted

 I'm using visual studio 2015. I want to get the result set in sqldatareader. Here is my code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

using System.Data;
using System.Data.SqlClient;

public partial class ADO2 : System.Web.UI.Page
{
SqlConnection cn = null;
SqlCommand cmd = null;
SqlDataAdapter dr = null;
string sqlCommandText = string.Empty;
protected void Page_Load(object sender, EventArgs e)
{
cn = new SqlConnection("Data Source=DELL;Database=ASPDB;User Id=sa;Password=123");
}

protected void button1_Click(object sender, EventArgs e)
{
sqlCommandText = "Select * from Dept,Select * from Emp";

if (cn.State != ConnectionState.Open)
cn.Open();
cmd = new SqlCommand(sqlCommandText, cn);

dr = cmd.ExecuteReader();
}
}

Answer 1

User2103319870 posted

SqlDataAdapter dr = null;

Try using SQLDataReader instead of DataAdapter

SqlConnection cn = null;
			SqlCommand cmd = null;
			//Here use DataReader instead of DataAdapter
			SqlDataReader dr = null;
			string sqlCommandText = string.Empty;
			protected void Page_Load(object sender, EventArgs e)
			{
				cn = new SqlConnection("Data Source=DELL;Database=ASPDB;User Id=sa;Password=123");
			}

			protected void button1_Click(object sender, EventArgs e)
			{
				sqlCommandText = "Select * from Dept,Select * from Emp";

				if (cn.State != ConnectionState.Open)
					cn.Open();
				cmd = new SqlCommand(sqlCommandText, cn);

				dr = cmd.ExecuteReader();
			}

Answer 2

User-1838255255 posted

Hi Manishamani,

Through your code and exception, if you want to use command.ExecuteReader method, like A2H's reply, you could replace SqlDataAdapter dr = null; with SqlDataReader dr=null. 

Also if you want to use SqlDataAdapter, please check the follow tutorial about how to get the data use SqlDataAdapter: 

Populating a DataSet from a DataAdapter: 

https://docs.microsoft.com/en-us/dotnet/framework/data/adonet/populating-a-dataset-from-a-dataadapter 

Best Regards,

Eric Du