How can I convert this PHP code to C# in Visual Studio Windows Form

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I have a somewhat okay knowledge in Php but I recently started Visual Studio and I was wondering how would I go about converting my code to Visual Studio. I wanted to create a combo box that will print out the main category then the sub category under it then the items under it and so on until all main categories are finished. I had no idea how to write them on C# so I first created the code in PHP and tried to dissect them.

So far my current code in Visual Studio is:

C#

private void Form1_Load(object sender, EventArgs e)
{
sc.Open();

//For Main Category
SqlCommand get_maincategory_name = new SqlCommand("SELECT * FROM maincategory", sc);
SqlDataReader dr2 = get_maincategory_name.ExecuteReader();
while (dr2.Read())
{
comboBox1.Items.Add(dr2["maincategory_name"].ToString());

//For Sub Category
SqlCommand get_subcategory_name = new SqlCommand("SELECT * FROM subcategory WHERE maincategory_id='1'", sc);
SqlDataReader dr3 = get_subcategory_name.ExecuteReader();
while (dr3.Read())
{
comboBox1.Items.Add("--" + dr3["subcategory_name"].ToString());

//For Inventory
SqlCommand get_inventory_name = new SqlCommand("SELECT * FROM inventory WHERE subcategory_id='1'", sc);
SqlDataReader dr4 = get_inventory_name.ExecuteReader();
while (dr4.Read())
{
comboBox1.Items.Add("----" + dr4["item_name"].ToString());
}
}
}
sc.Close();
}

My PHP code looks like this:

PHP

echo "<select>";

// FOR MAIN CATEGORY
$maincategory_query = mysqli_query($con,"SELECT * FROM maincategory") or mysqli_error();
while($got = mysqli_fetch_assoc($maincategory_query))
{
$maincategory_id = $got['maincategory_id'];
$maincategory_name = $got['maincategory_name'];
echo "<option disabled>$maincategory_name</option>";

// FOR SUB CATEGORY
$subcategory_query = mysqli_query($con,"SELECT * FROM subcategory WHERE maincategory_id='$maincategory_id'") or mysqli_error();
while($got = mysqli_fetch_assoc($subcategory_query))
{
$subcategory_id = $got['subcategory_id'];
$subcategory_name = $got['subcategory_name'];
echo "<option disabled>--$subcategory_name</option>";

// FOR ITEM
$item_query = mysqli_query($con,"SELECT * FROM item WHERE subcategory_id='$subcategory_id'") or mysqli_error();
while($got = mysqli_fetch_assoc($item_query))
{
$item_id = $got['item_id'];
$item_name = $got['item_name'];
echo "<option>----$item_name</option>";
}
}
}
echo "</select>";

The problems I'm having:
1. It's only showing the first main category name and nothing else.
2. I'm currently figuring out how to put dr2["maincategory_id"] (to replace the 1) inside the sql statement under WHERE but I'm having trouble figuring out what's the syntax on how it wouldn't be interpreted as a string.
3. I don't know how to disable(or to make read-only) certain parts of the combo box.

Posted 15-Oct-15 4:19am

Flex Luthor

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Comments

Amit Jadli 16-Oct-15 1:44am

You could simply put that value like '"+ dr2["maincategory_id"] +"'

Sinisa Hajnal 16-Oct-15 3:25am

Do you really need all categories and subcategories in the same dropdown? Wouldn't it be better to load each as needed? In several dropdowns containing hierarchy of categories?

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Sinisa Hajnal · Answer 1 · 2015-10-15T21:21:00

This is not how you bind comboboxes in .NET.

You should do something like this:

C#

SqlCommand getMainCategoryName = new SqlCommand("SELECT * FROM maincategory", sc);
DataSet ds = new DataSet;
SqlDataAdapter da = new sqlDataAdapter;
da.SelectCommand = getMainCategoryName ;
da.Fill(ds);

// display member is the column that will show in the combobox
cboMainCategoriesDisplayMember = "maincategory_name";
// value member is the column that will be the value of the combobox
cboMainCategories.ValueMember = "maincategory_id"
cboMainCategories.DataSource = ds; // you may put ds.Tables[0];

Note that control names are now non-default meaningful names. I've named variables as I prefer, you can keep yours of course :). I would suggest you change your id fields to integer, but again, your choice. It helps with sorting by ID and joins are faster.

You can write dr2["maincategory_id"].ToString(); to get the string out of the column.