Member Name	Description
Input	The parameter is an input parameter. This is the default.
Output	The parameter is an output parameter.
Input/Output	The parameter can perform both input and output.
Return Value	The parameter represents a return value from an operation such as a stored procedure, built-in function, or user-defined function.

Note: SQL Server has only two-parameter direction Input and Output.

Parameter Data Types

In the above code I have used SqlDbType of the Parameter object.

The data type of a parameter is specific to the .NET Framework data provider. Specifying the type converts the value of the Parameter to the .NET Framework data provider type before passing the value to the data source.

Begin your application by launching VS.NET and creating a new project using File - > Project and choose C# Windows Application template as shown in figure below:

Add a new item application configuration file as shown below from Project -> Add New Item

The code for the application configuration file:

<?xml version="1.0" encoding="utf-8" ?>

<configuration>

<connectionStrings>

<add name="constr" connectionString="initial catalog=puran; data source=MCN002; integrated security=sspi"/>

</connectionStrings>

</configuration>

Note: In the above code I have made a connection using windows authentication.

Design the form as below:

Add the necessary reference file from the solution explorer, Reference as below:

Code for displaying records in a database through textbox using parameterized query in disconnected model.

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using System.Configuration;

using System.Data.Common;

using System.Data.SqlClient;

namespace shwing_records_disconnected

{

public partial class Form1 : Form

{

public Form1()

{

InitializeComponent();

}

SqlConnection con;

SqlCommand cmd;

private void button1_Click(object sender, EventArgs e)

{

con = new SqlConnection(ConfigurationManager.ConnectionStrings["constr"].ConnectionString);

cmd = new SqlCommand();

cmd.Connection = con;

cmd.Parameters.Add(new SqlParameter("@RollNo", SqlDbType.Int));

cmd.Parameters["@RollNo"].Value = textBox4.Text;

cmd.Parameters.Add(new SqlParameter("@Name", SqlDbType.VarChar,50));

cmd.Parameters["@Name"].Direction = ParameterDirection.Output;

cmd.Parameters.Add(new SqlParameter("@Fees", SqlDbType.Float));

cmd.Parameters["@Fees"].Direction = ParameterDirection.Output;

cmd.CommandText = "select @Name=Name, @Fees=Fees from student where RollNo=@RollNo";

con.Open();

cmd.ExecuteNonQuery();

textBox1.Text = cmd.Parameters["@RollNo"].Value.ToString();

textBox2.Text = cmd.Parameters["@Name"].Value.ToString();

textBox3.Text = cmd.Parameters["@Fees"].Value.ToString();

con.Close();

MessageBox.Show("Record Displayed");

}

}

}

Advantages of parameterized commands:

• Parameterized commands can also improve query execution performance, because they help the database server accurately match the incoming command with a proper-cached query plan.
• Parameterized command provide security and performance benefits.
• Parameterized commands provide a convenient method for organizing values passed to a data source.

Note: I have attached code of the above program. You have to create table and change the necessary database connection string in configuration file.

Conclusion

After reading this article you might be clear about command object, benefits of parameterized command, DbParameter Object, ParameterDirection Property and Parameter Data Types in ADO.NET using SQL Server as database.

Your feedback and constructive contributions are welcome. Please feel free to contact me for feedback or comments you may have about this article.