Autofill TextBox based on another TextBox in ASP.Net

Hi ShihabKhan,

Please refer below sample.

HTML

<div>
    Designation:
    <asp:TextBox ID="txtDesignation" runat="server" AutoPostBack="true" OnTextChanged="AutoFill"></asp:TextBox>
    <br />
    Name:
    <asp:TextBox ID="txtName" runat="server"></asp:TextBox>
    <br />
    <asp:Label ID="lblMessage" runat="server" ForeColor="Red" />
</div>

Code

C#

protected void AutoFill(object sender, EventArgs e)
{
    if (txtDesignation.Text.ToLower() == "programmer")
    {
        txtName.Text = "Mudassar Khan";
    }
    else
    {
        lblMessage.Text = "No record";
    }
}

VB.Net

Protected Sub AutoFill(ByVal sender As Object, ByVal e As EventArgs)
    If txtDesignation.Text.ToLower() = "programmer" Then
        txtName.Text = "Mudassar Khan"
    Else
        lblMessage.Text = "No record"
    End If
End Sub

Screenshot