Check whether a character is present in String (Text) using C# .Net

Hi Anand,

I have made a sample that full-fill your requirement.

HTML

<div>
    Enter Value :
    <asp:TextBox ID="txtValue" runat="server" />
    <br />
    Enter Key:
    <asp:TextBox ID="txtKeyWord" runat="server" />
    <br />
    <asp:Button ID="btnCheck" Text="Check" runat="server" OnClick="CheckKeyAvailability" />
    <br />
    <asp:Label ID="lblResult" runat="server" Visible="false" />
</div>

Code

protected void CheckKeyAvailability(object sender, EventArgs e)
{
    string value = txtValue.Text.Trim();
    string key = txtKeyWord.Text.Trim();
    string result = string.Empty;
    int index = value.LastIndexOf(key);
    if (index != -1)
    {
        result = value.Substring(0, index + key.Length);
    }
    if (!string.IsNullOrEmpty(result))
    {
        lblResult.Text = result;
    }
    else
    {
        lblResult.Text = "Key not found";
    }
    lblResult.Visible = true;
}

Screenshot

Hope this will help you.