将excel数据直接读入gridview，每列显示超过255个字符的完整数据

using System.Data;
using System.Data.OleDb;

private DataTable ReadExcelData(string filePath)
{
    string connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + filePath + ";Extended Properties=\"Excel 12.0;HDR=YES;IMEX=1;\"";
    using (OleDbConnection connection = new OleDbConnection(connectionString))
    {
        connection.Open();
        DataTable dataTable = connection.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
        string sheetName = dataTable.Rows[0]["TABLE_NAME"].ToString();
        string query = "SELECT * FROM [" + sheetName + "]";
        using (OleDbDataAdapter adapter = new OleDbDataAdapter(query, connection))
        {
            DataTable excelData = new DataTable();
            adapter.Fill(excelData);
            return excelData;
        }
    }
}

string excelFilePath = "路径/文件名.xlsx";
DataTable excelData = ReadExcelData(excelFilePath);
GridView1.DataSource = excelData;
GridView1.DataBind();

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False">
    <Columns>
        <asp:TemplateField HeaderText="列名">
            <ItemTemplate>
                <asp:Label ID="Label1" runat="server" Text='<%# Bind("列名") %>'></asp:Label>
            </ItemTemplate>
        </asp:TemplateField>
        <!-- 其他列定义 -->
    </Columns>
</asp:GridView>