The parameterized query expects the parameter which was not supplied
Building on and simplifying ravidev's answer:
The VB.NET shorthand is:
cmd.Parameters.AddWithValue("@Department", IF(TextBox2.Text, DBNull.Value))
The C# shorthand is:
cmd.Parameters.AddWithValue("@Department", (object)TextBox2.Text ?? DBNull.Value)
If you pass null value to parameter,you will get this error even after you add the parameter so try to check the value and if it null then use DBNull.Value
This will work
cmd.Parameters.Add("@Department", SqlDbType.VarChar)
If (TextBox2.Text = Nothing) Then
cmd.Parameters("@Department").Value = DBNull.Value
Else
cmd.Parameters("@Department").Value = TextBox2.Text
End If
This will convert the null values from the object layer to DBNull values that are acceptable to the database.
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Your query problem is the least of your concerns right now.
But.....
@Misnomer's solution is close but not quite there:
Change your query to this:
cmd.CommandText = "SELECT * FROM borrow where (Department LIKE '%@DepartmentText%')"
and add parameters this way (or the way that @Misnomer does):
cmd.Parameters.AddWithValue("@DepartmentText",TextBox2.Text)
The important difference is that you need to change your CommandText.