How To Create TextBox Control Dynamically at Runtime

In Technique when creating control dynamically in a Page Load event

handler these controls will retain their ViewState after the

PostBack, but what if controls created dynamically at runtime in a

Button Click event handler instead of Page Load event then on

PostBack these controls ViewState are lost.To persists the

ViewState of these child controls we will recreate these controls

again on a PostBack in overrideable CreateChildControls() Method

which is called whenever

ASP.NET needs to create these WebControl in a Control Tree.

// Add TextBoxes Control to Placeholder

private void CreateTextBoxes()

{

for (int counter = 0; counter <= NumberOfControls; counter++)

{

TextBox tb = new TextBox();

tb.Width = 150;

tb.Height = 18;

tb.TextMode = TextBoxMode.SingleLine;

tb.ID = "TextBoxID" + (counter + 1).ToString();

// add some dummy data to textboxes

tb.Text = "Enter Title " + counter;

phTextBoxes.Controls.Add(tb);

phTextBoxes.Controls.Add(new LiteralControl("<br/>"));

}

}

In CreateTextBoxes method I loop through ‘n’ numbers of controls that we wants to create dynamically in phTextBoxes placeholder.

// Create TextBoxes on PostBack.

protected override void CreateChildControls()

{

// Here we are recreating controls to persist the ViewState on every post back

if (Page.IsPostBack)

{

NumberOfControls += 1;

CreateTextBoxes();

}

else

{

CreateTextBoxes();

// Increase the control value to 1

NumberOfControls = 0;

}

}

CreateChildControls method, here we are recreating control on every

PostBack. If the page is created the first time we just create these

controls and save 1 in the ViewState so we know that we have created

these controls and assigned the controls id to 1.

// Increase the counter when button is clicked and add to view

state

protected void btnAddTitle_Click(object sender, EventArgs e)

{

NumberOfControls += 1;

}

In button event handler we just increase the counter by 1, and save its value to ViewState for later retrieval.
Once we have created these controls on ASP.NET page, retrieving data from these dynamically created controls is easy by using FindControl method.

// Read TextBoxes Data

private void ReadTextBoxes()

{

int n = NumberOfControls;

for (int i = 0; i <>

{

string boxName = "TextBoxID" + (i + 1).ToString();

TextBox tb = phTextBoxes.FindControl(boxName) as TextBox;

strValue += tb.Text +”\n”;

}

}