How to Databind multiple Checkboxlist into a Gridview [closed] - for-loop

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ERROR: Getting output table show some blank rows in each column after the first column.
This code works as, there is 4 checkboxlist each of it containing 4 list item. When selecting each of the list item it should be displayed in the
specified column .
Right Output: Each column with specified rows in the right position
private void button1_Click(object sender, EventArgs e)
{
Form2 fm = new Form2();
DataTable dt = new DataTable();
dt.TableName = "FoodOrder";
dt.Clear();
dt.Columns.Add("WelcomeDrinks");
dt.Columns.Add("Starter");
dt.Columns.Add("MainMeals");
dt.Columns.Add("Desserts");
for (int i = 0; i < chk1.Items.Count; i++)
{
if (chk1.GetItemChecked(i))
{
DataRow row = dt.NewRow();
row["WelcomeDrinks"] = (string)chk1.Items[i];
dt.Rows.Add(row);
}
}
for (int i = 0; i < chk2.Items.Count; i++)
{
if (chk2.GetItemChecked(i))
{
DataRow workrow = dt.NewRow();
workrow["Starter"] = (string)chk2.Items[i];
dt.Rows.Add(workrow);
}
}
for (int i = 0; i < chk3.Items.Count; i++)
{
if (chk3.GetItemChecked(i))
{
DataRow row = dt.NewRow();
row["MainMeals"] = (string)chk3.Items[i];
dt.Rows.Add(row);
}
}
for (int i = 0; i < chk4.Items.Count; i++)
{
if (chk4.GetItemChecked(i))
{
DataRow row = dt.NewRow();
row["Desserts"] = (string)chk4.Items[i];
dt.Rows.Add(row);
}
}
fm.Grid1.DataSource = dt;
fm.Show();
}

Answer 1

You are neglecting to take into account how many rows you need in the table. Using your current approach where a new row is added for each checked box item in each check box list, then you end up such that only ONE item will be on each row. The first check box items will have their own row and so will each check box list. It may look something like…
Welcome Drinks Starter MainMeal Desserts
Welcome Drinks 1
Welcome Drinks 2
Starter1
Starter3
Main Meal 1
Main Meal 4
Dessert 3
Dessert 4
Is what you need to do is check each CheckedListBox and figure out which check box list has the GREATEST number of items checked. This will tell you how many rows you need in the table. Then, instead of “adding” new rows in the for loops through each list, simply add the item to the existing row using the column name to determine which cell the value goes in.
To get the list check box with the greatest number of “checked” items may look something like…
int maxRows = chk1.CheckedItems.Count;
if (chk2.CheckedItems.Count > maxRows)
maxRows = chk2.CheckedItems.Count;
if (chk3.CheckedItems.Count > maxRows)
maxRows = chk3.CheckedItems.Count;
if (chk4.CheckedItems.Count > maxRows)
maxRows = chk4.CheckedItems.Count;
Then add that number of rows to the table.
for (int i = 0; i < maxRows; i++) {
dt.Rows.Add();
}
Now the table should have the proper number of columns and rows.
Since we know we have to loop through each CheckedListBox to get the “checked” items, it may help if we create a method that takes a string for the column name we want to put the values, the CheckedListBox and the DataTable and returns nothing.
This AddColumnData method, would loop through each of the “checked” items in the given CheckedListBox and add the items to the data table starting on the first row and the given column name. This method may look something like…
private void AddColumnData(string colName, CheckedListBox checkedListBox, DataTable dt) {
int curRowIndex = 0;
DataRow row;
foreach (var checkedItem in checkedListBox.CheckedItems) {
row = dt.Rows[curRowIndex++];
row[colName] = checkedItem;
}
}
With this method, it will make it easier to add the items to the table as shown below…
AddColumnData("WelcomeDrinks", chk1, dt);
AddColumnData("Starter", chk2, dt);
AddColumnData("MainMeals", chk3, dt);
AddColumnData("Desserts", chk4, dt);
I hope this makes sense.