ASP.NET FAQ - TextBox

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(I don’t understand ‘tyring to insert/update data’, ‘webcontrol is not associated with it’s property’!)
//
if you write code using parametrized query as
paramxxx.value = textbox1
it’ll show above error
to resolve it it should be
paramxxx.value =textbox1.text

//This kind of error message can occur when you are trying to insert/update data or any kind of operation which involves textbox/dropdownlist
The issue occurs if the webcontrol is not associated with its property

May be you have not associated the appropriate property of the control
i.e textBox1.Text
or dropdownlist1.SelectedItem.Value

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For security reason, TextBox with TextMode=’Password’ setting cannot be assigned or populated via the Text property on Page_Load or PostBack event.

It’s not recommend for to prefill a ‘Password’ type TextBox with the(‘***’) characters, though below is the solution to achieve this.

VB.NET


ViewState('Pwd')=TextBox1.Text ;
TextBox1.Attributes.Add('value', ViewState('Pwd').ToString ()) ;

C#


ViewState['Pwd']=TextBox1.Text ;
TextBox1.Attributes.Add('value', ViewState['Pwd'].ToString ()) ;
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<asp:TextBox id='TextBox1' style='Z-INDEX: 101; LEFT: 0px; POSITION: absolute; TOP: 112px' runat='server' TextMode='MultiLine'></asp:TextBox>
<asp:RegularExpressionValidator id='RegularExpressionValidator1' style='Z-INDEX: 102; LEFT: 216px; POSITION: absolute; TOP: 112px'
	runat='server' ErrorMessage='MaxLength is 20' ControlToValidate='TextBox1' 	ValidationExpression='^\w{1,20}
>
</asp:RegularExpressionValidator>

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<script lang='javascript'> 
function CheckFunction() 
{ 
if (document.getElementById(’<%=textbox2.ClientID%>’).value == '') 
{ 
	alert('Please enter a value'); 
	return; 
} 
} 
</script> 



<asp:textbox id='textbox2' runat='Server'></asp:textbox> 
<input type=button id='btn1' onclick='javascript:CheckFunction();' value='Click'>

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<asp:TextBox id='TextBox1' BackColor =<%#colCon.ConvertFromString(bgcolor)%> runat='server'>
</asp:TextBox>

VB.NET


Protected colCon As New System.Drawing.ColorConverter
Protected bgcolor As String = '#556600'

’In Page_Load
Page.DataBind()

C#


protected  System.Drawing.ColorConverter colCon =new System.Drawing.ColorConverter();
protected string bgcolor    = '#556600';

//In Page_Load
Page.Databind();
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Product ID : <asp:TextBox id='TextBox1' style='Z-INDEX: 101; LEFT: 80px; POSITION: absolute; TOP: 64px' runat='server'></asp:TextBox>
Product Name:<asp:TextBox id='TextBox2' style='Z-INDEX: 102; LEFT: 80px; POSITION: absolute; TOP: 112px' runat='server'></asp:TextBox>

VB.NET


’Populate the DataSet
’...

’Display in TextBoxes using Column Name
TextBox1.Text = ds.Tables (0).Rows(0)('ProductId').ToString ();
TextBox2.Text =ds.Tables (0).Rows(0)('ProductName').ToString (); 

’Display in TextBoxes using Column Index
TextBox1.Text = ds.Tables (0).Rows(0)(0).ToString ();
TextBox2.Text =ds.Tables (0).Rows(0)(1).ToString (); 

C#


//Populate the DataSet
//...

//Display in TextBoxes using Column Name
TextBox1.Text = ds.Tables [0].Rows[0]['ProductId'].ToString ();
TextBox2.Text =ds.Tables [0].Rows[0]['ProductName'].ToString (); 

//Display in TextBoxes using Column Index
TextBox1.Text = ds.Tables [0].Rows[0][0].ToString ();
TextBox2.Text =ds.Tables [0].Rows[0][1].ToString (); 

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Id : <asp:TextBox id='TextBox1' style='Z-INDEX: 102; LEFT: 128px; POSITION: absolute; TOP: 32px' runat='server'></asp:TextBox>
Name : <asp:TextBox id='TextBox2' style='Z-INDEX: 103; LEFT: 128px; POSITION: absolute; TOP: 72px' runat='server'></asp:TextBox>

VB.NET


Dim cn As SqlConnection
Dim cmd As SqlCommand
Dim rdr As SqlDataReader

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
	’ Put user code to initialize the page here
	Try
		cn = New SqlConnection('server=localhost;uid=sa;pwd=;database=northwind')
		cmd = New SqlCommand('select * from Products where productid =1', cn)
		cn.Open()
		rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection)
		rdr.Read()
		TextBox1.Text = rdr('ProductId').ToString()
		TextBox2.Text = rdr('ProductName').ToString()
	Catch ex As Exception
		Response.Write(ex.Message.ToString())
	Finally
		rdr.Close()
		cn.Close()
	End Try
End Sub 

C#


SqlConnection cn ;
SqlCommand cmd ;
SqlDataReader rdr ; 
private void Page_Load(object sender, System.EventArgs e)
{
	// Put user code to initialize the page here
	try
	{
		cn = new SqlConnection('server=localhost;uid=sa;pwd=;database=northwind');
		cmd = new SqlCommand( 'select * from Products where productid=1 ', cn);
		cn.Open();
		rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection );
		rdr.Read ();
		TextBox1.Text =rdr['ProductId'].ToString ();
		TextBox2.Text =rdr['ProductName'].ToString ();
	}
	catch (Exception ex)
	{
		Response.Write (ex.Message.ToString ());
	}
	finally
	{
		rdr.Close();
		cn.Close();
	}
}
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<asp:PlaceHolder id='PlaceHolder1' runat='server'></asp:PlaceHolder>

VB.NET


Dim textboxes(5) As TextBox
Dim i As Integer
For i = 0 To 4
   	textboxes(i) = New TextBox()
	textboxes(i).ID = 'TextBox' + i
   	textboxes(i).AutoPostBack = True
   	PlaceHolder1.Controls.Add(textboxes(i))
Next 

C#


TextBox[] textboxes = new TextBox[5]; 
for (int i=0; i<5; i++) 
{ 
	textboxes[i] = new TextBox(); 
	textboxes[i].ID = 'TextBox' + i; 
	textboxes[i].AutoPostBack = true; 
	PlaceHolder1.Controls.Add(textboxes[i]); 
}
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VB.NET


Dim ctl As Control
For Each ctl In Page.Controls(1).Controls
            If TypeOf ctl Is TextBox Then
                CType(ctl, TextBox).Text = ''
            End If
Next

C#


foreach (Control ctl in Page.Controls[1].Controls )
{
	TextBox tb = ctl as TextBox;
	if (tb!=null)
	{
	tb.Text = '' ;
	}
}

Note: Page.Controls[1]=> control is within the

tag

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