Dynamically change HeaderText of ASP.Net GridView using C# and VB.Net

Hey akhter,

Please refer below sample.

HTML

<asp:GridView ID="Gridview1" runat="server" AutoGenerateColumns="true" OnDataBound="Gridview1_DataBound">
</asp:GridView>

Namespaces

C#

using System.Data;

VB.Net

Imports System.Data

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    DataTable dt = GetDataTable();
    Gridview1.DataSource = dt;
    Gridview1.DataBind();
}

private static DataTable GetDataTable()
{
    DataTable dt = new DataTable();
    dt.Columns.AddRange(new DataColumn[] { new DataColumn("5-1-2019", typeof(string)), new DataColumn("6-1-2019", typeof(string)), new DataColumn("7-1-2019", typeof(string)), new DataColumn("8-1-2019", typeof(string)) });
    dt.Rows.Add("p", "A", "p", "A");
    return dt;
}

protected void Gridview1_DataBound(object sender, EventArgs e)
{
    DataTable dt = GetDataTable();
    for (int i = 0; i < Gridview1.HeaderRow.Cells.Count; i++)
    {
        for (int j = 0; j < dt.Rows.Count; j++)
        {
            for (int k = 0; k < dt.Columns.Count; k++)
            {
                if (Gridview1.HeaderRow.Cells[i].Text == dt.Columns[k].ToString())
                {
                    Gridview1.HeaderRow.Cells[i].Text = Gridview1.HeaderRow.Cells[i].Text.Split('-')[0];
                }
            }
        }
    }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    Dim dt As DataTable = GetDataTable()
    Gridview1.DataSource = dt
    Gridview1.DataBind()
End Sub

Private Shared Function GetDataTable() As DataTable
    Dim dt As DataTable = New DataTable()
    dt.Columns.AddRange(New DataColumn() {New DataColumn("5-1-2019", GetType(String)), New DataColumn("6-1-2019", GetType(String)), New DataColumn("7-1-2019", GetType(String)), New DataColumn("8-1-2019", GetType(String))})
    dt.Rows.Add("p", "A", "p", "A")
    Return dt
End Function

Protected Sub Gridview1_DataBound(ByVal sender As Object, ByVal e As EventArgs)
    Dim dt As DataTable = GetDataTable()
    For i As Integer = 0 To Gridview1.HeaderRow.Cells.Count - 1
        For j As Integer = 0 To dt.Rows.Count - 1
            For k As Integer = 0 To dt.Columns.Count - 1
                If Gridview1.HeaderRow.Cells(i).Text = dt.Columns(k).ToString() Then
                    Gridview1.HeaderRow.Cells(i).Text = Gridview1.HeaderRow.Cells(i).Text.Split("-"c)(0)
                End If
            Next
        Next
    Next
End Sub

Screenshot