Passing value to SQL query parameter from my textbox

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Hi,
I am using following code to connect to my database.

<pre lang="vb"> Dim conStr As String = "Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\dbTest.mdf;Integrated Security=True;User Instance=True"
     Dim sqlQry As String = "SELECT * FROM [tblTest] WHERE ([Name] = @Name)"
       Dim dAdt As New SqlDataAdapter(sqlQry, conStr)
    Dim dSet As New DataSet()

Then filling adapter with

<pre lang="vb">dAdt.Fill(dSet, "tblTest")

and then I can use the data the way I want.

My question is:
How to pass the value of parameter that user will give through a text box.

C#

Dim sqlQry As String = "SELECT * FROM [tblTest] WHERE ([Name] = @Name)

"

I mean how to pass the parameter value to my query?
Please modify my code to tell me how to do it.
Thanks a lot.

Posted 8-Sep-11 23:31pm

Furqan Sehgal

Updated 9-Sep-11 0:58am

Pravin Patil, Mumbai

v2

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Pravin Patil, Mumbai · Answer 1 · 2011-09-09T01:06:00

Solution 2

There are two ways to do so :

Solution 1 :

Dim sqlQry As String = "SELECT * FROM [tblTest] WHERE [Name] = " + textBox1.text

Solution 2 :

Dim sqlQry As String = "SELECT * FROM [tblTest] WHERE [Name] = @Name"

Dim command As New SqlCommand(sqlQry, connection)

' Add Name parameter for WHERE clause.
command.Parameters.Add("@Name", SqlDbType.Varchar, 20) -- 20 Refers to the size
command.Parameters("@Name").Value = textBox1.Text

Hope this helps.
All the best.

Posted 9-Sep-11 1:06am

Pravin Patil, Mumbai

Comments

Furqan Sehgal 9-Sep-11 7:23am

First method you suggested says
Object reference not set to an instance of an object.

Now I try second

Furqan Sehgal 9-Sep-11 7:25am

Second method gives error on command (Declaration Expected). I wonder why this happens despite we have declared it on line above.
But when I moved it to button1_click, declaration error removed but it did not work in that case. It gave scaler error on dataadapter filling statement

Herman<T>.Instance · Answer 2 · 2011-09-08T23:35:00

Solution 1

see here: http://vbnetsample.blogspot.com/2007/10/using-sqlparameter-class.html[^]

Posted 8-Sep-11 23:35pm

Herman<T>.Instance

Wendelius · Answer 3 · 2011-09-09T09:42:00

When you use parameters (and that's exactly what you should do) you should define a SqlCommand object separately and use that command for your data adapter. So the whole code could look something like:

VB

Dim conStr As String = "Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\dbTest.mdf;Integrated Security=True;User Instance=True"
Dim sqlQry As String = "SELECT * FROM [tblTest] WHERE ([Name] = @Name)"
Dim dAdt As New System.Data.SqlClient.SqlDataAdapter()
Dim dSet As New DataSet()
Dim queryCommand As New System.Data.SqlClient.SqlCommand()
Dim queryConnection As New System.Data.SqlClient.SqlConnection()

queryConnection.ConnectionString = conStr
queryConnection.Open()
queryCommand.Connection = queryConnection
queryCommand.CommandText = sqlQry
queryCommand.Parameters.AddWithValue("@Name", textBox1.Text)
dAdt.SelectCommand = queryCommand
dAdt.Fill(dSet)
queryConnection.Close()

Remember to replace textBox1.Text with your actual text box object.

Also opening the connection, executing the fill etc should be enclosed to proper try..catch block