从表中读取多个数据并创建表格形式的文本框

Question

My table in MySQL is like this:

I have a panel in my Form, and I want to create a TextBox for each data on this table and write sikicerik data to that TextBox's text. Actually I did it but it creates only one TextBox and selects only the first data on the table.

My code is like this:

int count = oku.FieldCount;

reader.Read();
{
    for (int i = 0; i < count; i++)
    {
        TextBox txt1 = new TextBox();
        Point txtyer = new Point(x, y);
        txt1.Text = reader["sikicerik"].ToString();
        txt1.Name = i.ToString();
        x = x + 25;
        y = y + 25;
        panel1.Controls.Add(txt1);
    }
}

It creates just one TextBox and writes "5" in it.

How can I do that repeatedly?

Answer 1

What you need to understand is that you need to call reader.Read() after going through each record. Let's say your result data set has 5 records, so in order to read the 1st record, you need to call reader.Read() which would populate the reader object with the appropriate data. In order to read the 2nd record, you need to again call reader.Read() . Something like this:

int count = reader.FieldCount;

for (int i = 0; i < count; i++)
{
    reader.Read();
    TextBox txt1 = new TextBox();
    Point txtyer = new Point(x, y);
    txt1.Location = txtyer;
    txt1.Text = reader["sikicerik"].ToString();
    txt1.Name = i.ToString();
    y = y + 25;
    panel1.Controls.Add(txt1);
 }

The reason why you may not be able to view all TextBoxes is that you are updating both x and y coordinates of the TextBox. What you may probably want to do is just increment the y coordinate as above and all the TextBoxes would appear vertically. You may also want to resize your form so that the TextBoxes don't get hidden.

Also, as @Steve mentioned in the comments above (which I missed), you need to assign the location of the new TextBoxes created as is done in the code above.

Answer 2

I suppose that you get the FieldCount from the reader variable.

Now in this context you should loop over the read and inside the loop create the textbox for each field retrieved by the original query.

Finally, if you don't set the Location property of the TextBoxes they will be created each on top of the others and you see only the topmost one with the latest value obtained in the loop

// Get the number of fields present in the reader....
int count = reader.FieldCount;

// Read one record at time
while(reader.Read())
{
    // Create a textbox for each field in the record
    for (int i = 0; i < count; i++)
    {
        TextBox txt1 = new TextBox();

        // Set its location on screen
        // Probably if you have many fields you need to 
        // use a better algorithm to calculate x,y position 
        txt1.Location = new Point(x, y);
        txt1.Text = reader[i].ToString();
        txt1.Name = i.ToString();
        x = x + 25;
        y = y + 25;
        panel1.Controls.Add(txt1);
    }
}

If you want to create textboxes only for the field sikicerik you have two options. The first one is the recommended because it causes less overhead on your database consist in changing the SELECT query used to build the read to

 SELECT sikicerik FROM yourTableName

The other option is a simple change to your code. You don't need to loop over FieldCount because you already know that you are interested in only one field

// Read one record at time
while(oku.Read())
{
    textBox1.Text = oku["soru"].ToString();
    label1.Text = Form2.sinavno;

    // Create the single textbox required for the only field required
    TextBox txt1 = new TextBox();

    // Set its location on screen
    txt1.Location = new Point(x, y);
    txt1.Text = oku["sikicerik"].ToString();
    txt1.Name = i.ToString();
    x = x + 25;
    y = y + 25;
    panel1.Controls.Add(txt1);

    // Repeat the loop for each record.

}