Conversion failed when converting the varchar value 'System.Data.DataRowView' to data type int

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Hello Codeproject Member ,

I am trying to populate data from sql in a C# windows form according to the selection made by the user in a combobox , though I have managed to successfully bind the combobox to the database , but I am not able to populate the data in the textboxes according to the selection of an item from combobox.
When I run program the error I am getting is--->
SqlException was unhandled by user code -"Conversion failed when converting the varchar value 'System.Data.DataRowView' to data type int."
My code is as following

//Database Table

1) id-int-notnull (primary key and autogenerate id)
2) name-varchar-notnull
3) mobile-numeric-notnull
4) address-varchar-notnull

private void Form2_Load(object sender, EventArgs e)
    {
        SqlConnection conn = new SqlConnection(@"Database path.............");
        conn.Open();
        SqlCommand command = new SqlCommand("select * from customer", conn);
        SqlDataAdapter adp = new SqlDataAdapter(command);
        tbl = new DataTable();
        adp.Fill(tbl);
        comboBox1.DataSource = tbl;
     comboBox1.ValueMember = tbl.Columns[0].ColumnName;
 }
    private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
    {
        SqlConnection conn = new SqlConnection(@"Database path...............");
        conn.Open();
       SqlCommand command = new SqlCommand("select name,mobile,address from customer where id=@id", conn);
    command.Parameters.AddWithValue("@id", comboBox1.SelectedValue.Tostring());
        SqlDataAdapter adp = new SqlDataAdapter(command);
        DataSet ds = new DataSet();
        adp.Fill(ds, "customer");
        textBox1.Text = ds.Tables["customer"].Rows[1]["name"].ToString();
     textBox2.Text = ds.Tables["customer"].Rows[2]["mobile"].ToString();
        textBox3.Text = ds.Tables["customer"].Rows[3]["address"].ToString();
       }

Posted 1-Apr-14 9:00am

manish7664

Updated 1-Apr-14 9:05am

Richard C Bishop

v2

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Maciej Los 1-Apr-14 15:38pm

--posted by mistake---

2 solutions

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Richard C Bishop · Accepted Answer · 2014-04-01T09:16:00

Solution 1

The problem is occurring because the parameter value is not getting set to what you are probably expecting. Your "id" column in the table is an int datatype and that is what you need to pass it. See code below:

int comboBoxChoice = Convert.ToInt32(comboBox1.SelectedValue.ToString());
command.Parameters.AddWithValue("@id", comboBoxChoice);

Now provided your combo box is getting a value, this should do the trick.

Posted 1-Apr-14 9:16am

Richard C Bishop

Updated 1-Apr-14 9:17am

v2

Comments

manish7664 1-Apr-14 15:29pm

Thanks for reply. I made changes as per your suggestion but it's showing error
Error -Input string was not in a correct format.

Richard C Bishop 1-Apr-14 15:31pm

Ok, that means you are not getting the expected value upon your comboBox choice. What are the possible values available for it?

Maciej Los 1-Apr-14 15:36pm

Sounds reasonable, +5!

Richard C Bishop 1-Apr-14 15:38pm

I thought so, thank you Maciej!

manish7664 1-Apr-14 15:47pm

Mr Richard guide me how can i remove Input string was not in a correct format error

Maciej Los 1-Apr-14 15:48pm

Please, see my answer (Solution 2)

Richard C Bishop 1-Apr-14 15:53pm

See Maciej Los solution below. This is what I was talking about, your combox value not being persisted to where you expected.

Maciej Los · Accepted Answer · 2014-04-01T09:47:00

Solution 2

There are known issues with ComboBox.Selected<Something> properties. Have a look here: ComboBox SelectedItem, SelectedValue, SelectedWhat???[^]

Quote:
SelectedValue - This property depends on the value of ValueMember.

If the property ValueMember is not Nothing the ComboBox will look for a member on SelectedItem with the name specified in ValueMember and return that. This is also the value displayed in the ComboBox.

I'd suggest you to use Int32.TryParse[^] method or better to deal with SelectedItem or SelectedIndex property.

Posted 1-Apr-14 9:47am

Maciej Los

Comments

Richard C Bishop 1-Apr-14 15:52pm

Great addition. I suspected there was an issue with the value getting persisted from the combobox. +5

Maciej Los 1-Apr-14 15:57pm

Thank you, Richard ;)

manish7664 2-Apr-14 2:51am

Thanks Mr Maciej and Mr Richard. but int32.tryparse not taking here.
int comboxchoice = Int32.TryParse(comboBox1.SelectedItem.ToString());
command.Parameters.AddWithValue("@id", comboxchoice);

Maciej Los 2-Apr-14 3:00am

Foolow the link and do proper convertion.

manish7664 2-Apr-14 7:44am

now my code run successfully but i have one problem when i select id from combobox then "System.Data.DataRowView" showing in textbox instead of database value.
i request you that please tell me what mistake i am doing in code....
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
SqlConnection conn = new SqlConnection(@"Data Source=MANISH-PC\SQLEXPRESS;Initial Catalog=test2.mdf;Integrated Security=True");
conn.Open();
SqlCommand command = new SqlCommand("select name from table1 where id=@id", conn);
int comboxchoice;
Int32.TryParse(comboBox1.SelectedIndex.ToString(), out comboxchoice);
command.Parameters.AddWithValue("@id", comboxchoice);
SqlDataAdapter adp = new SqlDataAdapter(command);
DataSet ds = new DataSet();
adp.Fill(ds, "customer");
textBox1.Text = comboBox1.SelectedValue.ToString();
}

Maciej Los 2-Apr-14 8:39am

SelectedIndex is not the same as SelectedValue. Please see: http://msdn.microsoft.com/en-us/library/system.windows.forms.combobox.selectedindex%28v=vs.110%29.aspx
SelectedIndex gets or sets the index specifying the currently selected item (position on the list, not value binded with database!).

manish7664 3-Apr-14 2:14am

i used below code and it's working fine. Thanks once again both of you.
int comboxchoice = Convert.ToInt32(comboBox1.SelectedIndex);
command.Parameters.AddWithValue("@id", comboxchoice);
textBox1.Text = comboBox1.SelectedValue.ToString();