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supriyasinha
Starting Member
1 Post |
 Posted - 2011-07-12 : 05:46:03
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| it dsplyng error "Conversion from type 'DBNull' to type 'String' is not valid. " its not updating my database when it is empty but if value is thier it get updated... shows error in line cmd4.Connection = cnn4 cmd4.CommandText = "Select distinct(ch_ro) from name_list1 where region='" & ddlRegion.SelectedValue & "' and country='" & ddlCountry.SelectedValue & "' and site='" & ddlSite.SelectedValue & "'" cnn4.Open() TextBox8.Text = cmd4.ExecuteScalar() cnn4.Close()and my update command is str2 = " update name_list1 set " & _ "ch_it_mnr='" & TextBox4.Text & "',ch_ldba='" & TextBox5.Text & "',ch_rdba='" & TextBox7.Text & "',ch_ro='" & TextBox8.Text & "'," & _ "ch_gdba='" & TextBox9.Text & "',ch_gldba='" & TextBox10.Text & "',ch_lo='" & TextBox11.Text & "',ch_la='" & TextBox12.Text & "',ch_soc='" & TextBox13.Text & "'," & _ "snc_it_mnr='" & TextBox14.Text & "',snc_ldba='" & TextBox15.Text & "',snc_rdba='" & TextBox16.Text & "',snc_ro='" & TextBox17.Text & "',snc_gdba='" & TextBox18.Text & "'," & _ "snc_gldba='" & TextBox19.Text & "',snc_lo='" & TextBox20.Text & "',snc_la='" & TextBox21.Text & "',snc_soc='" & TextBox22.Text & "' where region='" & ddlRegion.SelectedValue & "' and country='" & ddlCountry.SelectedValue & "' and site='" & ddlSite.SelectedValue & "'" cmd2 = New SqlCommand(str2, conn) conn.Open() cmd2.ExecuteNonQuery() conn.Close() MsgBox("Update successfully")please help me its urgent....before their was no error nd it was workng pefctly but not now, dn't knw hw to solve this..thanks supriya |
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sunitabeck
Master Smack Fu Yak Hacker
5155 Posts |
Posted - 2011-07-12 : 07:04:15
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This is because you are not getting any result from your first query - the "cmd4.ExecuteScalar()". Change your code to....cnn4.Open()object o = cmd4.ExecuteScalar();if (o != DBNull.Value){ TextBox8.Text = o.ToString();}else{ TextBox8.Text = string.Empty;}cnn4.Close()I have written it in C#, if you are using VB, you will need to change the syntax appropriately. Of course, whether that is the correct logic or not, I don't know. |
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mohdowais
Sheikh of Yak Knowledge
1456 Posts |
Posted - 2011-07-12 : 09:14:26
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| Directly concatenating strings in this manner to create your SQL leaves you open to SQL Injection attacks. Please read more about creating parameterized queries and how to avoid SQL injection attacks. https://www.owasp.org/index.php/Top_10_2010-A1OS |
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Conversion from type 'DBNull' to type 'String' is