SelectedValue and comboboxen

[redspiderke]

Hi, I want to fill the 2nd combobox with values dependent on the value from the first combobox In reallife: The first combo contains car brands, the second a list of types. I want that when I select Ford I only get the types from Ford

// Vul comboboxes
private void GetVtgMerken()
{
txtBrand.DataSource = _Brand.GetVtgBrand();
txtBran.DisplayMember = "Brand_Name";
txtBran.ValueMember = "Brand_ID";
}
private void GetVtgBrandTypes(int ID)
{
txtType.DataSource = _Brandtype.GetVtgBrandTypes(ID);
txtType.DisplayMember = "type_Naam";
txtType.ValueMember = "MT_Id";
}

    // Fill the second combo 
    private void txtBrand\_SelectedIndexChanged(object sender, EventArgs e)
    {
        // first debug
        textBox1.Text = txtBrand.SelectedValue.ToString();

             // first attempt
             int ID = Convert.ToInt32(txtBrand.SelectedValue.ToString());
             // second attempt
             int ID = Int32.Parse(txtBrand.SelectedValue.ToString());
             
       // the new select
        GetVtgMerkTypes(ID);
    }

When I use Convert.toInt32 or int32.parse I always get the error like below. System.FormatException: Input string was not in a correct format. Textbox1.text displays the value correct (ex. 3) Is there someone who can help ?

[V 0]

What's the value of txtBrand.SelectedValue.ToString() ? Check if it is really a number (meaning digits only) if it contains letters, you'll need to perform additional formatting or use another container then int for ID.

V.

[Luc Pattyn]

conversion methods will throw a FormatException when the input string isn't in the right format, which includes the case where the input is empty. e.g. you may get that while your Form gets loaded. It is often solved easily by including a non-zero-length test in your code. :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

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[redspiderke]

When I do:

textBox1.text = txtBrand.SelectedValue.ToString()

the textbox shows the value "3". An integer I think :) But when I convert the textbox to an variable the debugger complains.

Kan een object van het type System.Int32 niet converteren naar het type System.Data.DataRowView.

After a long search i fixt it like this:

private void txtBrand_SelectedIndexChanged(object sender, EventArgs e)
{
if (txtBrand.SelectedValue is DataRowView)
{
string BrandID = Convert.ToInt32(((DataRowView)txtBrand.SelectedValue)["Brand_Id"]).ToString();
int ID = Convert.ToInt32(BrandID);
GetVtgMerkTypes(ID);
}
else
{
int ID = Convert.ToInt32(txtBrand.SelectedValue.ToString());
GetVtgMerkTypes(ID);
}
}

... this works :-)

[redspiderke]

Luc, I think you are right !!! I fixt it with the code below:

    private void txtBrand\_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (txtBrand.SelectedValue is DataRowView)
        {
            string BrandID = Convert.ToInt32(((DataRowView)txtBrand.SelectedValue)\["Brand\_Id"\]).ToString();
            int ID = Convert.ToInt32(BrandID);
            GetVtgBrandTypes(ID);
        }
        else
        {
            int ID = Convert.ToInt32(txtBrand.SelectedValue.ToString());
            GetVtgBrandTypes(ID);
        }
    }

maybe not nice but it works :)